Domain Expansion

longer the ability is active it takes away heath by 2 but the longer you have it makes it stronger by 

Sukuna's Domain Expansion, For the first round this is active take off 5 health, for every additional round multiply the damage by two. So two rounds equals 10 dmg, 3 rounds 20, 4 rounds 40, and so on.

You can add an additional 100ft, but you take double dmg. This deal can be done indefinitely.

You can also take this deal to add 1d10 to dmg, but yet again, you take double dmg. this deal is also indefinite.