User blog comment:Munster Bunny/Quirk Creation Blog/@comment-38710794-20200115195630

Quirk: Fusion

Type: ???

Description: I got this idea from Steven Universe. It is basically the same thing as fusion in Steven Universe, except they can pass down the ability genetically. It is different in that the two parent's quirks decide the offspring's new quirk. Fusion is sort of like One For All or Half-Cold Half-Hot - two different quirks join together to make one cohesive unit. When someone with the fusion quirk has a child with someone who has a different quirk, all they can pass down is the "fusion" part of the quirk. The other partner's quirk is then just added on to the child's ability to fuse. This prevents a quirk from building upon itself (prevents things from getting too OP). For example, a fire controlling fusion has a child with someone who can launch spikes from their skin - the child would be a spike launching fusion, not a fire controlling fusion that can launch spikes too. However, if a fusion and a fusion have a child together, the child can fuse forcefully with other people and control the unstable fusion's actions on their own (Malachite from SU).

Strengths: Combat oriented. Incredibly versatile. Easy to hide second part to quirk.

Weaknesses: Fusions can become unstable - same rules to SU fusion apply here. Fusion is an incredibly personal thing to do. The longer you stay in a fusion, the more you disassociate from your personal identity and it becomes harder to unfuse.

Downsides: Incredibly personal and an emotional time bomb. Some people forced quirk marriage to create strong offspring, while others use fusion as an emotional crutch. Some from a double fusion union have turned to villainy (specifically kidnapping) and abuse of others. Of course, there are also others forced to fuse and stay fused for so long the original people no longer exist (this is also about the only way to build up a fusion's quirk).