User blog comment:DeathGodPrayer/Talk About What You Want!/@comment-80.181.161.74-20121225163512

I'm confused about 3 things:

1) From Vol 12 Issei is a dragon/devil hybrid, this mean that is like Tannin or something similar?

2) Dragon have a limitless lifespan, this make Issei, Tannin and other "dragon-like" devil with a lifespan more long compared to reincarnated and pure blood devils?

3) Here someone say that Phenex Family and Gremory Family make a secret deal setting an "arranged marriage" making Rias the first wife and Ravel the second, if this thing is true than devils can marry more than one person?

someone help me to clear this points