Eris got an unusually cruel and prolonged death scene, as per historical standards of this show--though things will only escalate from here. Kind of a waste of a character, though--had they revealed Eris as a white mage follower of Rezo earlier on, we could have had a nice thematic conflict (and more than likely an interesting set of battles) between the black magic sorceress who fights mostly for good, vs the white magic cleric consumed by revenge and power. It would have even given Sylphiel a nice context to chew on! Ah, well.
But you have to wonder--if OG Rezo's plan was to have Zanaffar fight it out with Shabby Dabby Doo, then he seriously had
no idea his eyes were a vessel for the latter, huh? At best, his body would've been torn apart between Shabranigdo and Zanaffar fighting over it to possess it; at worst, they would have merged and become an even bigger threat. And also, even if Zanaffar
was his trump card, then why did he go and use the Philosopher's Stone at the tower so far removed from his lab, where he didn't have access to his wards and tools?
Oh, and I did find it amusing how, a couple episodes ago, Sylphiel was adamant against Lina attempting the Giga Slave again, since a miscast would destroy existence. But then, when Lina actually goes and casts it, Sylphiel all but
tackles her during the incantation, forcing Lina to nigh-miraculously hold it in. Way to almost destroy existence in trying to prevent Lina from destroying existence, Syl!
Copy Rezo wants to kill Lina to prove he's better than the original, so basically he wants to anime-fight the protag to prove he's STRONGER which makes his motivations a bit more shonen-y for this series.
Somewhere in Kanzaka and Araizumi's notes there must be an alternate Slayers where Copy Rezo became the very tall Vegeta to Lina's very short Goku and on the one hand, we were robbed of the comedy potential, on the other, I'm glad we didn't get that version because the story is already so very heavily skewed towards magic-using munchkins as it is.