I don't think it matters before level 35, because it will be over soon. If you want to use the blood training hall, you can use scorpions, and it is not bad to suck highly toxic blood. At level 45, you will use Changshoutang. At a lower level, I don't think it's much use to use French babies. At level 55, prostitutes and robots can be used. If you don't have much money, it is recommended to use evil spirits. At the age of 65, you can get unicorns and tigers if you have money. I think Kirin and Hupu 95 are both blood babies, which is useless!