That Time I got reincarnated as Cu Chulainn with a slime (not a story but Idea)

So, I was browsing reincarnated as a slime fanfic and I saw a picture for one that made me think of cu, and I thought, "why not have a fanfic were someone reincarnates with rimuru as Cu chulainn from fate and has Gae Bolg and all Cu's skills.