Assuming this is the cockroach from post #886857. Deep-ass cut, and the second OC with a 2hu form (after the cow)
Gonna guess that Goki-chan here is gonna save Patchy by freaking out Flan, then turn and expect to be rewarded... only for patchy to try and kill her too.
Can cockroaches become youkai if they survive for a hundred years?
For most youkai types, especially just generic types. 100 years tends to be the minimum go to years to become a youkai. Coins, leftover garbage, statues, Even a tree that was beloved by a village (or around a lot of magic) can all turn into Youkai.