FicWad

Harry Potter/ D&D crossover
Mechanics
+Potterverse "wizards" are Titans with most of their SLAs and such swapped out for an at-will Wish SLA.
+Potterverse "giants" are Mountain Giants (MM2, colossal dimwitted giants of great power).
+Harry Potter after changes is mechanically a potterverse wizard with an elemental template added to represent the addition of the blood of the king/progenitor of X Giants.

Plot
+Potter accepts a deal, either from Ymir like Tiamat fic or something left behind post-mortem by Sirius. Result is he ends up gaining powers from blood of Ymir/Surt giving him strong elemental powers in associated element.
+Part of deal is that he leaves plane. If deal is from Sirius then his godfather has probably tried to set up something to help him once he gets to a specific destination. If from Giant King he probably only knows that he's supposed to go out and do impressive things in the name of Y.
+Either case he will probably end up with a group of "monster race" characters.