This has been a topic since his introduction. Is Karasu Zoan or what?
To me he reminded me of several characters:
1. Alucard from Hellsing
Notice how Alucard has Hellhounds coming from his body? Now look at Karasu:
Notice how the crows are in the extension of his body like with Alucard?
This brings me to the conclusion that he isn’t a regular Zoan.
2. Gekko Moria
Take a look at this picture:
Do you notice something strange?
Karasu is literally deforming himself and transforming into crows.
This ability has been seen with Gekko Moria who used his Doppelganger to do the same.
- Brick Bat (literally meaning “Fragment Bats”): Moriah transforms Doppelman into a myriad of ball, which turn into a swarm of bats that can attack an opponent. Because the bats are so small, numerous, and immortal, this attack is very difficult to counter or avoid, and the constant annoyance can make opponents get fatigued quickly. After being used, the bats can merge to reform Doppelman. This was first seen being used against Luffy.
3. Karasu’s first encounter
Take not what I said in the previous point that Karasu himself transforms into crows.
When we first saw this, we presumed Sabo was talking to someone via crows.
We were wrong, he was talking to Karasu the whole time. Karasu is the crow Sabo is flying on.
Karasu has a mythical Zoan devil fruit that enables him to create crows like shadows out of his body or even transform his body into crows themselves.
*Theory by Beky