How strong is Magellan?
For me, he's at least YC2,
and at most YC1.
And he would defeat characters like Fujitora, Blackbeard, and Aramaki because of the power of their special abilities (if they were caught off guard).
He defeated and annihilated Blackbeard's entire crew with a single blow.
And later, Teach had to defeat him using the entire crew and prisoners.