User blog comment:BannedLagiacrus/Monster Appreciation Week: Monoblos(4th Gen)/@comment-5020152-20151121004313/@comment-6050823-20151121013442

^ That is true! In order to unlock Diablos in MH1, you need to make a one piece of Monoblos Armor.

I will also add that there is two other relatives of Monoblos and Diablos, Varusaburosu and, their distant cousin, Gravios.