Because im lazy and dont feel like rewording Wikipedia i will just leave a link to the rathalos wiki page if you want technical info on this dude ^.=.^ ))
Size Reference
Rathalos wiki page
(( Picture found on google, not mine ))
Roku is just your average rathalos in everything but size, that of which he is bigger than most of his kind. He can understand english but cannot speak it, he does however use bodily gestures to get the point across. He avoids and is suspicious of all humans given how they like to hunt his species along with other down, a healthy suspicion but a suspicion non the less. Despite his wariness to humans he does enjoy some of the things they have created, namely the massively diverse food they come up with and most music.
A quick way to get this wyvern to not kill you is to show that you dont mean harm (though he will still sometimes try to kill you) and bribing him with food (he has a massive sweet tooth). If you enter his territory he will try to chase you away (rare) or try to kill and eat you (main jist).
If you somehow get through all that without him killing you he isnt all that bad, hell he is actually quiet nice when he isnt trying to kill you (though aren't most animals that way). He enjoys rubs though the places you can rub are scarce given how many spikes and scales he has.
He is fiercely protective of both his territory and those he holds close, which means that your either a tree in his home or a creature he hasn't killed (which means he sees you as his ). Him showing affection will come either in the form of licks and nuzzles or him attempting to mate you and unless your big enough to take it i would avoid him if its option two.
In theory he is big enough for someone to ride him but unless you have a specially made saddle (and he agree to it) you wont want to ride him, spikes and plates dont make good seats in most instances. If you manage to take him as a "pet" you will have a hard time feeding him and training him since he is both a glutton and is smart as any human.
