A girl named Riley gives you an egg of him/her mine was a him and so was my brothers.
You don't find it, the mans name is Riley, he has a lucario and other rare pokemon. Riley gives you an egg that is rilu.
Rilu's population is 3,153.
Go to Iron Island and meet Riley in the cave. Beat the grunts on the way. Towards the end of the cave with the elevator. When Riley says goodbye. He'll give you a rilu egg to hatch.(Also Riley will keep your Pokemon heathy on the trip)Hopefully this will help you.
If you're talking about Riolu, I believe it evolves with happiness.
levle 50 sorry if it doesent work I DONT REALY KNOW
if you mean riolu, yes and no. it ONLY evolves when leveled up with high friendship between 4:00 am and 8:00 pm. I hope this helped, good luck!
1. don't deposit on your PC 2. battle lot's of trainers with it 3. don't use rare candies to level it up 4. don't let it die 5. you can check your pokemons feelings at the house next to pastoria city