Sure thing. But just so you know, that's not how it is. "I've become... a monster" Not "I'd become a monster." It really doesn't make sense that way. If you're using past tense, it becomes redundant if you use past tense words more than once per clause. So in my example, it's either be "I became a monster," or "I have become a monster." Not saying that's what I used as an incorrect example right now, but that's what you did in the comment I first corrected. Edit: Had become is present perfect, have become is present progressive, so neither are wrong if you use them the right way. Your "Have became" is still wrong though because you meant past progressive the moment you said "over 100 years ago" but you instead used past progressive and past perfect simultaneously.