Arthas by mynamereallysux

Block: Periodically reduces damage of Hero Basic Attacks by 50%. Stores 2 charges.
Winter Winds: Increases the root duration Howling Blast by 1 second. Also disables Minions and Mercenaries for 2 seconds, Structures for 4 seconds.
Mortal Coil: If an enemy dies within 1 second after being hit by Death Coil, permanently increase it's damage and healing by 2, up to a maximum of 240.
Regeneration Master: Collecting Regeneration Globes permanently increases Health Regeneration by 1.5 per second.

Destruction: Damage boost from Frostmourne Hungers increased to 150% and deals 25% of that damage to nearby enemies.
Frozen Wastes: Frozen Tempest Mana cost reduced by 35 per second and increases max stacks by 2.
Immortal Coil: DOWN (Lvl 16) Death Coil also heals when used on enemies. When used on self, the amount healed is increased by 50%.
Mercenary Lord: Non-Boss Mercenaries near your hero deal 50% more damage. Reduces damage taken from Minions and Mercenaries by 50%.

Death's Touch: Death Coil causes Minions to explode, killing the target and dealing (possibly half, wouldn't nerf till tested) it's normal damage to other nearby enemies.
EternalHungerSoul Reaper:  Mana restored by Frostmourne Hungers increased to 6080. If the target is a Hero, Frostmourne Hungers also does up to 80 Mana damage to the target and drains 25% of their Ability Power for 3 seconds.
Frost Strike: Frostmourne Hungers also slows the target by 40% for 1.5 2.5 seconds. Also disables Minions and Mercenaries for 5 seconds, and Structures for 10 seconds.
Rune Tap: Every third Basic Attack heals you for 3.12% of your max Health.

Encumbering Frost: Each Stack of Frozen Tempest slows enemy Attack Speed by 5%. This affects enemy Structures.
Embrace Death: DOWN (Lvl 16) Death Coil does 20%10% more damage for each 10% life you are missing.
Relentless: Reduces the duration of silences, stuns, slows, and roots against your Hero by 50%.
Spell Shield: Upon taking Ability Damage, reduce that damage and further Ability Damage by 50% for 3 seconds. Can only trigger once every 30 seconds.

Frost Presence: UP (Lvl 1) Howling Blast cooldown lowered by 3 seconds. Can now hold 2 charges.
Biting Cold: UP (Lvl 13) Each stack of Frozen Tempest damage increased by 50%increases its damage by 10%.
Frostmourne Feeds: Increased application to your next 2 Basic Attacks.
Stone Skin: Activate to gain 30% of your maximum Health as a Shield for 5 seconds.

Absolute Zero: Sindragosa flies twice1.5 times as far and breathes 1.5 times as wide. Heroes are rooted for 2 seconds, and then slowed by 60% for 2 seconds.
Legion of Northrend: 34 additional Ghouls are created. Ghouls heal for an additional 25% Health and last 510 seconds longer.
Hardened Shield: Activate to reduce damage taken by 75% for 4 seconds.
Unholy Aura: Increase nearby allies Move Speed by 10% and regeneration effects by 100%. Reduces nearby enemies healing effects by 20% and prevents health regeneration.

Changes to Frozen Tempest Talents
Frozen Tempest didn't really use its "increasing over time" effect very well. I added that mechanic to Biting Cold, as well as a new talent. Encumbering adds an alternative to Spell Shield/Relentless vs a heavy Auto-Attack team. Frozen Wastes Mana cost reduction (from 3 -> 5) should make it much more viable, but adding 2 stacks has the added benefit of synergizing with the base skill and future talents pretty strongly. 2 more stacks means...

Move Speed Slow: 30% @ 6 secs -> 40% @ 8 secs.
Encumbering Frost Slow: 30% @ 6 secs -> 40% @ 8 secs.
Biting Cold Damage: 60% @ 6 secs -> 80% @ 8 secs.

So it takes longer to get the full Move Speed Slow, and the Damage from Biting Cold, but investing multiple talents into Frozen Tempest is now rewarding.

Changes to Death Coil
Death Coil had a problem of talents just being in the wrong place. It also had some missing synergy with Death Touch. Adding Mortal Coil allows stacking, increasing damage and healing by up to 240 after killing 120 enemy units with it. Death Touch would obviously synergize with that, making it much easier to kill Minions and gain stacks through the splash damage. Overall damage increase would be good if you talent into it, and would only be about 5% less damage and healing if you didn't.

Death Coil damage @Lvl 20:
Live: 360 Damage @100%, 522 Healing
New: 342 Damage @100%, 495 Healing
Live Embrace Death @ 50% Health: 360 * 2 = 720 Damage
Live Embrace Death @ 10% Health: 360 * 2.8 = 1008 Damage
New Embrace Death @ 50% Health: 342 * 1.5 = 513 Damage
New Embrace Death @ 50% Health: 342 * 1.9 = 650 Damage
27 Damage less than Live @ 100% Health
207 Damage less than Live @ 50% Health
358 Damage less than Live @ 10% Health

Soul Reaper: 342 * 1.25 = 428 Damage
                        495 * 1.25 = 618 Healing
Soul+Embrace @ 50% Health: 342 * 1.25 * 1.5 = 641 Damage
68 Damage more than Live when Soul Reaper is active (vs Untalented)
79 Damage less than Live with both Soul Reaper and Embrace Death @ 50% Health

Max Mortal Coil: 342+240 = 582 Damage
                              495+240 = 735 Healing
Mortal+Embrace: 582 * 1.5 Damage = 873 Damage
222 Damage more than Live with Max Mortal Coil @ 100% Health
153 Damage more than Live with Max Mortal Coil and Embrace Death @ 50% Health

Mortal+Soul @100%: 582 * 1.25 = 727 Damage
Mortal+Soul+Embrace @50%: 582 * 1.25 * 1.5 = 1091 Damage
Mortal+Soul+Embrace @10%: 582 * 1.25 * 1.5 = 1382 Damage
367 Damage more than Live with all 3 talents @ 100% Health
371 Damage more than Live with all 3 talents @ 50% Health
374 Damage more than Live with all 3 talents @ 10% Health

So going with Mortal Coil and 1 of the 2 other Talents will be a net gain in damage. Getting Soul Reaper will give the added benefit of increased Healing and increased Damage on your other spells as well. Without Mortal Coil it's a damage nerf, but Healing would still be up if you get Soul Reaper, especially if combo'd with Immortal Coil.

Changes to Frostmourne Hungers Talents
The talents for Frostmourne Hungers were all eclipsed by better talents, except for Destruction and Frostmourne Feeds. Buffing all of the talents seems to be the best choice here, and in the case of Destruction, providing good alternatives.

Eternal Hunger (Now Soul Reaper) is moved to 7, and is given a Mana drain and an Ability Power drain. This is useful in harass, as well as being able to keep casting spells for either damage or healing. The Ability Power drain is unique in that it will buff all Arthas's Spell Damage and Healing from Death Touch, as well as weaken an enemy Hero. This gives Arthas more of a reason to be in the thick of battle. This Ability combined with Immortal Coil can even be picked as an alternative to Rune Tap, improving Arthas's sustain with constant Death Coils and restoring Mana.

With Immortal Coil on Level 4, Destruction is no longer going to be the top pick for Tank Arthas, being prioritized only if you want more damage. Immortal Coil is so strong at this tier, and given the small nerf to untalented Frostmourne Hungers damage, Destruction gets the remnants of Obliterate (25% splash instead of 50%).

Frostmourne Feeds gets some added utility with Soul Reaper and a small buff to Frost Strike. Frost Strike sits eclipsed by Rune Tap, a flat numbers buff was needed. 1.5s up to 2.5s is really good for a 40% slow. Frost Strike was also given a Merc/Structure disable similar to Sindragosa for flavor. Now you can slow twice, drain 80 mana twice, drain Ability Power twice, disable Structures twice, and deal massive damage twice.

Changes to Storm Talents
Legion of Northrend gets 1 more minion and lasts 5 seconds more to help balance it vs Hardened Shield. Sindragosa gets more width in exchange for some range, hopefully making it even more usable in team fights. Hardened Shield is still there, but Rewind is removed. Rewind had it's one use (Double Howling Blast) moved to Level 16.

Unholy Aura is an attempt at a new mechanic. Trying to stay true to the WC3 Death Knight, Unholy Aura increases mobility and sustain, with an added bonus of REDUCING HEALING EFFECTS of the enemy team. Could be too much, but it needs to be good to compete with Hardened Shield. Could be strong vs heavy healing comps, as well as help speed up pushes, take control of objectives, and catch opponents off guard (Late game Gank squad?).

Tank:
Regeneration Master/Block -> Immortal Coil -> Rune Tap -> Army of the Dead -> Spell Shield/Relentless/Encumbering Frost -> Stone Skin -> Hardened Shield/Legion of Northrend
Melee Bruiser:
Regeneration Master/Block -> Destruction-> Rune Tap -> Army of the Dead -> Any -> Biting Cold -> Hardened Shield/Legion of Northrend/Unholy Aura

These two builds are the current top build for Arthas, with the exception of Biting Cold being moved up to 16 and Immortal Coil down on 4. Meaning if you want to deal more damage, your picking against Immortal Coil and Stone Skin (for Destruction and Biting Cold). Full Tank Arthas should be stronger with Immortal Coil. Nerfs to untalented Howling Blast (-0.5s on root), untalented Frostmourne Hungers (-25% damage) and untalented Death Coil (approx -5% dmg and healing) to make him less overall useful and requiring some deviation from the Tank Build to get more CC, or Damage. 

Heavy CC/Ganker?:
Winter Winds -> Any -> Frost Strike/Soul Reaper -> Summon Sindragosa -> Any -> Frost Presence/Frostmourne Feeds -> Absolute Zero/Unholy Aura

No Tank Talents? Plenty of CC to make up for it. Level 4 is pretty open, Frozen Wastes would let you keep your slow up more often, and would synergize if you go All-In on Frozen Tempest. Destruction would be good as usual, and may still be necessary with the slight nerf to untalented Frostmourne Hungers. Immortal Coil is powerful at this tier and would help sustain your attacks, especially if you go for Soul Reaper (Would increase both Damage and Healing). 

You can still choose a defensive talent on Level 13. Encumbering for AA, Spell Shield for Burst, Relentless for Stun comps. Level 16 double Howling Blast or even Double Frost Strike slow would be deadly. Added benefit, Frostmourne Hungers, Howling Blast, and Sindragosa (Tempest slows Attack Speed of structures if you get Encumbering) all disable Minions and Structures, adding some nice synergy. Perhaps that Level 4 Talent could me MERC LORD!?!?! (Probs not).

Tempest:
Any -> Frozen Wastes -> Any -> Summon Sindragosa -> Encumbering Frost -> Biting Cold -> Any

Going for all of the Tempest Talents leaves you kind of in the middle in terms of damage and tanky-ness. You could easily take Regen Master on 1, Rune Tap, and Hardened Shield and be a walking, unkillable AOE Slow. Alternatively, Unholy Aura would synergize well, making it much easier to catch opponents in your slow field and counteracting the healing of opponents, letting your DOT take control. Adding Death Touch on 7 could make a powerful Lane Pushing Arthas, with CC and Damage for team fights.

Death Coil/Caster:
Mortal Coil -> Immortal Coil/Frozen Wastes/Destruction -> Death's Touch/Soul Reaper -> Summon Sindragosa -> Embrace Death -> Any -> Absolute Zero

A real Death Knight! Mortal Coil adds a stacking mechanic similar to Azmodan's, and combine with Death Touch it makes it easy to stack. You could choose Soul Reaper over Death's touch to go for maximum single target damage by draining an enemy Hero's Ability Power, although getting stacks will be much harder. See below for quick calculation. Immortal coil isn't necessary for max damage, so Frozen Wastes is a decent alternative if you want to go for Biting Cold on Level 16. Another alternative would be Destruction, Soul Reaper, and Frostmourne Feeds. This Arthas should be doing A LOT more damage than current Arthas with any of the variations.

(1200 seconds in a 20 minute game. Cooldown is 9 seconds. Realistically it might take ~12 seconds to kill a minion, leaving some leg room for mistakes. So with constant minion killing ... 1200 / 12 = 100 in 20 minutes. You get 2 stacks per kill so that would be 200 stacks. Somewhat doable but will be much less because of team fights. Could be worth it to get a 25% ability power bonus.)