what do you mean different types of twins?
Cerys and Emrys are heteropaternal twins, they have different fathers. Euna and Ezra are fraternal twins. Aleric and Aleron are identical twins. Dakota and Sage are mirror twins. And Idalia and Aderyn are a term called heteromaternal twins that I've made for this book since superpowers are involved.
Essentially, they have the same dad but different mothers but their mothers are the same person. Their moms are named Serafim (Idalia's mother) and Allisyn (Aderyn's mother) but Serafim and Allisyn are split from the same person (Seryn).
Seryn's superpower is to split herself into two people (Allisyn and Serafim), which she split during the conception process and could no longer recombine after both halves were far enough in that the pregnancies had established themselves.