IK I ANSWERED THIS DURING OUR WAIT FOR 6.2 but to write it all down; Thancred!!! Roku's first friend outside the ocean, and his best friend ever since. Roku and him have been sparring since the very beginning, when roku was just a gladiator with little experience fighting outside of water. In those days thancred won a lot, but did hold back and try to mentor roku through new fighting techniques even if their fighting styles were different due to their respective jobs. As time went on and Roku developed his own style and got stronger, they sparred as a way to keep up their skill, blow off steam, and catcy any missteps in each others technique. They do not go easy on one another, thancred especially would be upset if roku held out on him too much. Their sparring was very integral to roku's recovery after his death and revival in ultima thule, and likewise for thancred going from rogue to gnb. They will joke and poke fun at the other. Thancred is one of the very few people who is like...he can get roku to not be such a goody-two-shoes all the time. Chaotic energy between the two of them. Roku can and will play just a teeny bit dirty for the fun of it bc thancred will do the same. Tldr: Theyre friends and its fun to them!!!