LELOUCH - Still a brilliant, conceited tactician and go-getter. Even more ruthless and conflicted than in the original series. Woefully & painfully dishonest. Hates the current government and will do anything to stomp it out. He believes the ends justify the means.
SUZAKU - No longer Lelouch's yin in that they're really a lil more alike now. Still a soldier who fights for justice. But now he'll do underhanded things to achieve goals. He's become a rather reserved, calculated and wary young man.
Lelouch and Suzaku spend quite a bit of the R2 series hating on each other after things went sour at the end of the first series. Which just makes it all the more surprising when they go out of their way to spare or help one another when they are as Lelouch puts it: "arch rivals."
While at a ball in the Chinese Federation territory in ep 9, Zero/Lelouch comes face to face with the Prince of Britannia and decides to use the opportunity to his advantage. Zero tries to gain leverage over the Prince through his fav game: chess. Zero wagers that if he wins he gets Suzaku. Now really, if they're already bartering for people, he could have asked for ANYthing. Being a tactician he probably thought of at least 10 different things he could gain from this game that would help him and the recently relocated Japanese people in their new home. But he just wants Suzaku... Really Lelouch? Really?
What's really interesting is that Suzaku seems kinda ok with this.
In ep 13 Suzaku is questioned by Shirley to see who Lelouch's true friends are since she realized everyone's mind has been tampered with through the power of Geass. Knowing how long they're been friends, Shirley wants to know how Suzaku really feels about him.
POINT 3 SPOILERS
Their beautiful friendship deteriorates even more until ep 16 when Lelouch is at the end of his rope, frightened and in desperate need. Of all the people who admire him, worked with him, fought and died helping him, Suzaku is the only person on earth he can think of. The only person he trusts. The only real friend he's ever known. He realizes this and picks up the phone.
When someone you really care about hurts you, it cuts much deeper and the pain is far worse. Lelouch realizing his mistakes and pain his lies have cost, begs Suzaku for for help in & forgiveness in ep 17. For a conceited bitch like Lelouch, bowing or actually asking anyone for something is of course impossibly rare. But Suzaku is not quick to forgive. At all.
During this same scene Suzaku asks Lelouch some tough questions since now he feels Lelouch has never really been honest with him their whole lives. He asks him why he keeps saving his life at all these points throughout the series where just letting him die would have been way more convenient. Lelouch comes up with reasonable excuses for helping him time and again. But Suzaku immediately knows he's lying about all of them. Hmm what other reason could Lelouch have? Of course the same could be said about Suzaku. He's saved Zero so many times with so many excuses for while a man who killed his girlfriend & hundreds of thousands of people would need to be spared or helped. Let alone to personally help him so often. Nina who was in love with Suzaku's girlfriend Princess Euphemia, calls him on this in ep 9. He doesn't even have a good excuse by then.
Angrily, but genuinely putting aside their differences and past grievances for now, Suzaku is willing to side with him once again and help. Just as Lelouch is about to take Suzaku's offered hand, higher ups from the Britannian government rush in to capture him. They used Suzaku as bait without his knowledge to lure Zero knowing about their "abnormal relationship." Yes they really said that. You can only imagine the look on Lelouch's face when he thinks the only friend he has in all of creation has betrayed him.
Actually no, you don't have to imagine.
POINT 7 UBER SPOILERS
In episode 21 Lelouch succeeds in stopping the Emperors mad ambitions. After the dust settles it's just he and Suzaku and C.C.. She asks what the two of them plan to do now that the threat is over. Suzaku, supposedly still sore about Euphemia tries to pick a bone with Lelouch.
Suzaku: Yeah, Lelouch is Euphy's murderer...
Lelouch: And what of it?
The death of Euphemia and being lied to were Suzaku's main beef with Lelouch. But a month later they've clearly kissed & made up. By the end of the episode with no more discussion after what's basically Lelouch's "so?" they're cool again. Not just cool but at this point Lelouch grabs the power he always wanted and becomes emperor of britannia. His first decree is to make Suzaku his personal knight. In both series whenever a knight was chosen by a member of royalty the two were pretty much always romantically linked. Take that any way you want.
I really don't want to spoil any more of this series than I already have and certainly don't want to ruin the ending for anyone who hasn't seen it yet. So even though there are technically more points I can put here, I won't. Hope you enjoyed reading this as much as I enjoyed writing and coding it.