Takeshi (a.k.a. Tiger Claw) is a mutant tiger assassin/bounty hunter originating from Japan, a lieutenant of the Shredder and an enemy of the Ninja Turtles. He perfectly knows his profession, making him an extremely dangerous opponent. After Shredder's demise, he assumes leadership over the Foot Clan.
Imagine Thanos without the Infinity Stones. No army. No armor. No weapon. Just full on fists against fists. Pick any fictional character from any franchise or studio that could take on Thanos in a fight. It's something I could have thought of long ago. THere will be a level two on fighting Thanos WITH a weapon. A level 3 with armor. A level 4 with an army. A level 5 of just Thanos with the Infinity Gauntlet. And a level 6 with everything. REMEMBER: only pick franchises that have characters CAPABLE of fighting.
