Unaliasing war_hammer -> warhammer
Unaliasing warhammer -> hammer

Aliasing warhammer_(weapon) -> war_hammer
Implicating war_hammer -> hammer
Implicating war_hammer -> weapon
Implicating war_hammer -> melee_weapon

Reason:

First off, I assume the warhammer_(franchise) tag exists to differentiate it from the real life weapon. That differentiation doesn't need to exist. A warhammer is not a real thing, a war hammer (with a space) is. Both Wikipedia and the Oxford English Dictionary spell it with a space!

So to make things clear...a war_hammer is a real life medieval weapon, and warhammer is a copyright...we should make wiki articles clarifying this as well.

Many further aliases are required to untangle this gordian knot:

Unaliasing warhammer_40k -> warhammer_(franchise)
Unaliasing wh40k -> warhammer_(franchise)

These should not be aliased together. That's almost like combining Starcraft and Warcraft into a single tag. But mostly this is in preparation to nuke the unnecessary warhammer_(franchise) tag.

Aliasing warhammer_(franchise) -> warhammer
Aliasing warhammer_fantasy -> warhammer
Aliasing warhammer_fantasy_battle -> warhammer

Aliasing wh40k -> warhammer_40k
Aliasing warhammer40k -> warhammer_40k
Aliasing warhammer_40000 -> warhammer_40k

Finally...both games should implicate Games Workshop which is the company that created the Warhammer universe. This can serve as a catch-all tag for everything Warhammer-related.

Implicating warhammer -> games_workshop
Implicating warhammer_40k -> games_workshop