Oh, Voodoom. For such a cool pokemon, you deserved better...
Thundurus-Therian @ Life Orb
Ability: Volt Absorb
EVs: 252 SpA / 4 SpD / 252 Spe
Modest Nature
- Agility
- Thunderbolt
- Focus Blast
- Hidden Power Ice
252+ SpA Life Orb Togekiss Fire Blast vs. 0 HP / 4 SpD Thundurus-T: 194-229 (64.8 - 76.5%) -- guaranteed 2HKO
252+ SpA Life Orb Thundurus-T Thunderbolt vs. 252 HP / 4 SpD Togekiss: 400-476 (106.9 - 127.2%) -- guaranteed OHKO
You can tank a single hit and avenge the possessed doll in one hit as well...