Arrow Season 5: 4 Characters That Absolutely Cannot Die (And 5 That Can)
3. Nyssa Al Ghul
After being something of a regular doing the third season, Nyssa al Ghul, son of Ra's, appeared only a handful of times during Season 4, although still enough to make an impact.
She returned to Star City to help Oliver cure Thea's bloodlust, but in return he had to kill Malcolm Merlyn (which, of course, he didn't). All of it added up to the League disbanding, which wasn't really a bad thing since they weren't exactly a compelling part of the show.
While Katrina Law has always given a solid performance, I don't really know how much more there is to explore with Nyssa. Her relationships with both Lance sisters have been covered, as has her rivalry with Malcolm Merlyn, and while she could conceivably keep on popping up every now and then to help out Team Arrow, she won't become a permanent member, and killing the character off probably wouldn't impact things too much.