Zelda: Breath of the Wild

[Colossus]

I just defeated my first Lynel in the Coliseum Ruins last night. Pretty sweet.

I only found 2 red ones. Never found a blue one. Once you are far enough, you can wreck them for fun. It's amazing.

I found a blue one, but after he killed me and before I knew how to defeat him, I ran around him to get where I was going. You'll find one if you go searching for the areas where you recall memories.

Now that I think about it, I MIGHT have ran into a few. I didn't get too close and just shot it when an ancient arrow. 
Now that I do think about it, I think they're in Hyrule Castle as well (the enclosed spaces make it hard)