SUOH MIKOTO - Dubbed the "Red King," Suoh is an incredibly powerful, violent, but oddly laid back brawler who could care less about his title. He has a big heart and tends to be fiercely protective of those under him.
MUNAKATA REISHI - The "Blue King" in many ways is Suoh's polar opposite. He can be cold, calculating and revels in his own sadistic nature. He takes his title very seriously and despite his icy exterior can be oddly kind.
Without giving too much away for those who haven't seen this anime yet, the "king's" powers, while great are finite. By episode 3, Suoh's powers are already reaching critical mass. Once reached, this will likely kill everyone in a 30 mile radius or so. Munakata, the Blue king, sees it as his duty to warn him to tone it down. If not, he'll be imprisoned or killed.
Suoh, famed for being quick to punch and ask questions later, just goes with him to be either killed or jailed for life. That gif above, while played for laughs, wasn't an exaggeration at all.
Later, Munakata goes to visit his amazingly willing captive in jail in an attempt to reason with the usually hard-headed red king. Suoh suggestively promises to be? compliant on one condition.
So this is what's going through my head for that entire clip.
Their 'relationship' is pretty damn abnormal. If the above clips didn't clue you in already, Munakata really enjoys needlessly abusing Suoh. Yet Suoh seems to either not notice Munakata's violence towards him or flat out takes threats to his life as flirty banter. Munakata sociopathy takes on even more sexual undertones shortly after his visit with jail bird Suoh. Munakata's 2nd in command also suggests extreme violence and incredibly inhumane treatment against Suoh if he gets out of hand. Here's what Munakata said verbatim:
"Your violation of his basic human rights makes me shudder."
SPOILER: Surprise, no jail can hold Suoh and he basically walks out. Munakata warns him once more to end this "war" and stop using the power that will get him and many others killed. The scene is loaded with not at all subtle tension.
In light of the last clip, I made this just for fun.
Munakata has a habit of completely invading Suoh's space, like in every single scene they're in together.
For whatever reason, it's become an anime trope to have two men who've shown unresolved sexual tension share a smoke near the end. (See Ai no Kusabi, Gungrave etc.) What's more, one guy always lights the other's cig for him.
When Munakata's pleas fail to convince Suoh to stop, it's the only time he shows emotion other than cold disdain or perverse fascination. After that, he just gives up on stopping the war, leading his men, everything. He leaves his 2nd in command in charge of everything before sulking of-screen. Speaking of his 2nd in command, it's fairly clear she has some feelings for he Blue king, but she later laments why her feelings aren't reciprocated.
There are more points I could make, but I don't want to ruin the ending for anyone. Thanks for reading!