The core

The centre exists only on a character board: a weapon's has no central slot, just its tolerance gauge and its affinity choice. Where it exists, it is a slot like any other — the armoury numbers it 09 — and it takes a transfer module like the eight around it.

It is what gives the build its affinity: the label shown always derives from it, it is never picked separately.

Two families of cores coexist, and both are legitimate: the generic 3★ ones, with no element, often kept into the endgame, and the elemental 4★ and 5★ ones.