Jabba

"Disciple?" The Young Giant raised an eyebrow and looked at Robin for a few seconds, "you will have to add a few more words, what do I gain from that?"

There is no doubt that Robin is a genius and most likely a Heaven's Chosen, but this is for himself... What can he offer him that he can't gain on his own?

If he talks about age and life experiences, he is older than Robin, and if he talks about strength, he is much stronger than Robin. 

In fact, if he was the master in this relationship, it would seem more appropriate.

"You will be my right hand in my plans here. I will give you strength that you would never have attained in your life without me. I will give you knowledge, Too much knowledge that all the inhabitants of this planet wouldn't have gathered it even in another hundred thousand years... Are you with me?" Robin widened his eyes and spoke confidently, but didn't explain further