Chick Magnet: Casshern certainly has a lot of women following him around and/or sighing over him during the course of the story. The list includes Lyuze, Sophita, Lizabel, Janice, Ringo and Nico, not to mention Leda also thinks he's beautiful. And then there's Luna...
Driven to Suicide: Defied. He DID want to die and wanted Lyuze to kill him after the full force of him causing the Ruin hit him, but once she started doing some serious damage to him, his BerserkMode wouldn't let her finish the job. She would have died if Friender didn't save her.
The Grim Reaper: The finale has him deciding to play this role in the series' world.
Invincible Hero: Casshern was already the strongest robot before becoming immortal, so this should come as no surprise. The only times he ever gets defeated are when he’s actively seeking to get killed and even then, he still tends to win anyway by talking them down or his berserker mode activating. However, the focus of the show is never on the actual fighting and much more on the conflicts and motivations behind all it, so this trope is hardly detrimental to the series.
Living Forever Is Awesome: Reconstructed in the final episode. By then he's come to believe that the fear of death is what makes people truly alive and so he decides to become death itself so Luna and her immortals don't become complacent.
Person of Mass Destruction: He hates fighting, but once his Berserk Mode activates, he can rip entire armies to shreds with his bare hands without breaking a sweat.
Unstoppable Rage / Superpowered Evil Side: It's still not clear what, exactly, his 'Berserk Mode' is, but it's likely a mix of these. Very few things are capable of making him snap out of it, short of him butchering every living thing he sees.
It seems to be a "Combat Mode" of sorts that activates automatically whenever he enters a fight. Even if he chooses not to fight back, putting him under enough duress will also trigger it.
Who Wants to Live Forever?: His view is that the dispirited immortal robots—including himself—aren't truly alive, compared to the mortals who burn with the metaphorical "fire" of life.
Broke Your Arm Punching Out Cthulhu: Zig-zagged. She almost killed Casshern (even if he was actively trying to die at the time), but she eventually inflicted enough damage to trigger his Berserk Mode, and almost got herself killed shortly after. If Friender hadn't saved her, she would have never made it out alive.
Cool Big Sis: Becomes this to Ringo, though they aren't related.
Tsundere: Lyuze, once she decides she won’t kill Casshern just yet, begins showing a very gentle side to everyone but him, though at this point her hate for him has nothing to do with the affection of a tsundere. Of course, this all changes once they start traveling together and she falls in love with him, though she’s still a very mild example of a class B, and once she comes to terms with her feelings, and they sort it out, the violent streak goes completely away.
Who Wants to Live Forever?: At first, she wanted Luna to save her from the Ruin. Once she sees how twisted she's become, she quickly changes her mind, deciding it's not worth it if it is going to change who she is. What she has learned while traveling with Casshern makes this decision final.
Why Can't I Hate You?: See 'Tsundere.' She suffers a major internal conflict once she starts realizing she cares about Casshern and is torn between hating the person he was, and falling in love with the person he became post-amnesia. The fact that Casshern feels genuine remorse over everything he did makes it worse..
Nice Hat: He dons one for his fight with Casshern. He used to wear it all the time, until the Ruin happened.
Pyrrhic Victory: Yes, he achieved his goal of defeating Luna... though at the cost of the Ruin spreading and infecting everyone including himself, his empire collapsing into anarchy, him losing most of his power, and almost every single one of his followers have lost whatever loyalty they had to him.
Bitch in Sheep's Clothing: Post-resurrection Luna turns out to be this, having a disdain for everything affected by the Ruin, and death in general; she refuses to stay with her loyal bodyguard as he's dying, calling him disgusting.
Came Back Wrong: Even though she's immortal and can't permanently die, she felt everything and was traumatized by Casshern killing her. Now she finds victims of the Ruin 'disgusting,' wants to abolish death itself, and even appears to be in love with Casshern. Then again... who isn't at this point?
In Love with Your Carnage: Played with. A little too infatuated with Casshern, who brutally murdered her, but not because of the carnage itself.
Karma Houdini: One of the few characters who survives the series until the very end. Justified due to her immortality, and probably because her dying a second time would lead to an even worse calamity than what her first death caused.
Kick the Dog: Does this to Dune, her bodyguard, by not staying with him as he died.
Killer Rabbit: Not only did she regularly kill immortals in the past (even if she hated it and doing so eventually drove her crazy with guilt), she's the one who impales Leda after inflicting Body Horror on her.
Living Forever Is Awesome: She literally wants to abolish death because she's disgusted by it. This is in stark contrast to what she did pre-series, which was to remove immortality, which made her feel like a murderer. In the final episode Casshern deconstructed this idea by pointing out that living is different from being alive, and the robots in her town were listless layabouts.