Pilfer
... with magic family:
1. [pet]Gusting grimoire[/pet] - Shadow shock/Amplify magic/Curse of doom
2.[pet]Lofly libram[/pet] - Shadow shock/Amplify magic/Curse of doom
3.[pet]Count scribe[/pet] - Shadow shock/Amplify magic/Curse of doom
My favorite "3 books" team easy kills it in 12 rounds
... with beast family:
1. [pet]Corgnelius[/pet] - Bark/Cute face/Puppy parade
2. [pet]Lost netherpup[/pet] - Shadow shock/Howl/Maul
3. Any snake with 270+ speed
I desided to do this fight some exotic way, but it took some atemtps. So I started from Cute face and restarted fight before Pilfer missed his Antaen cannon. After it Corgnelius just spamed Puppy parade and dies exactly after next cannon. Netherpup started from shadow shock*2-howl-shadow shock till Pilfer dies.
...with humanoid family:
1. [pet]Lil' bad wolf[/pet] - Claw/Dodge/Howl
2. [pet]Sister of temptation[/pet] - Shadow shock/Curse of doom/Lovestuck
3. Any humanoid pet
Another fun fight. Start from Dodge, swap on Sister - Curse - Lovestuck, swap on Wolf - Howl - Dodge - Claw, swap on Sister... Eventualy wolf dies and Sister finishes Pilfer.
...with dragonkin family
1. [pet]Ageless bronze drake[/pet] - Devastate/Breath/Time stop
2. [pet]Nether faerie dragon[/pet] - Slicing wind/Life exchange/Moonfire
3. [pet]Sprite darter hatchling[/pet] - Slicing wind/Life exchange/Moonfire
Nice, nice. Devastate, swap on Nether - Slicing wind-Life exchange - Nether dies. Bronze drake - Time stop - Breath - Devastate, swap on Darter-Slicing wind-Life exchange - Darter dies. Bronze drake - Time stop - Breath - Devastate-Breath. Win.
... with flying family
1. [pet]Yellow moth[/pet] - Alpha strike/Cocoon strike/Moth dust
2. [pet]Bloodgazer hatchling[/pet] - Savage talon/Falcosaur swarm!/Predatory strike
3. [pet]Brilliant spore[/pet] - Reckless strike/Spiked skin/Explode
Any moth starts from Cocoon strike, swap on Bloodgazer - Swarm!-Savage talon-Predatory strike, Bloodgazer dies. Brilliant spore - Reckless strike- Explode. Moth - Cocoon strike-Dust-Alpha strike. Win.
... with undead family
1. [pet]Restless shadeling[/pet] (273 spd) - Shadow shock/Death and decay/Phase shift
2. [pet]Unborn Val'kir[/pet] - Shadow slash/Curse of doom/Haunt
3. [pet]Blighted squirrel[/pet] - any/any/Stampede
I created fun fight, but for some reasons it droped me out in round I had win. May be bug. So I created another one.

So, Phase shift-Death and decay, swap on Val'kir - Doom-Haunt, Squirrel-Stampede till Squirrel dies, Val'kir or Shade finishes Pilfer. Win.