Bluntborne

Bro I'm reading a Necromancer in Hogwarts fanfic and this made me double check which one I was reading

honestly its funny enough for me to overlook it

Another person already said but they're probably sorted into Hogwarts, Beauxbatons, or other less prestigious schools of magic.

exactly, might be the summer before canon starts, right before his trip

too much bulk and you become a larger target for spells, of course he better still have muscle

? Didn't they only know Filch took them after MC warned them and then they went and raided the office?

If it was Sirius, who is no longer imprisoned but would still be in shabby rags and looking unkempt, everybody would know. There was no description of the color of the eyes, sunkes yet intense yes, but no color, and same for the hair. So whether it is Grindelwald can only be ascertained if he either 1. Stumbles upon a portrait of an older Grindlewald, I think Dumbles confiscated the younger photo, or 2. Bring the portrait to Dumbledore as he's already proven to be knowledgable and trustworthy thus far.

the expanded rooms of the ship itself

Can't they go on deck?