ichidan verb, godan verb (-ru), intransitive verb
Internet slang derived from 勝つ, used in a playful or emphatic way. Most often seen in the fixed phrase これで勝つる ('with this, I win'). Rarely conjugates; when it does, it can behave as either an ichidan or godan verb.
この作戦なら、これで勝つる！
With this strategy, we've got this win!
I often see 'これで勝つる' online, but not many people actually use it in real life.