Reach handled “emotional connection” extremely badly. It tried hard to give every character (except Jun) memorable and emotional deaths, but in the end it didn’t work because we didn’t like the characters in the first place. I thought Kat’s death scene in itself would be very sad and touching… except that I had no interest whatsoever in the character. Jorge was epic, but uninteresting. I was glad when Carter and Emile died. Noble Six’s death slightly touched me, but he was the player after all.
If any character from ODST died, it would be more emotionally affecting. ODST handled its characters very well, and I would be genuinely upset if any of the characters died in the Reclaimer Trilogy.
Jacob Keyes and Johnsons’ deaths hit me hard. Miranda Keyes to some extent as well, although I didn’t particularly feel emotionally invested in her. I only felt sad because she represented her father.
If Master Chief died, I would be shaken pretty badly - which is probably enough reason to suspect that 343 will kill him off in Halo 6.
Cortarna too, she’ll probably die to upset the player, but that doesn’t make it any less sad.
If Jun returned and died, I would laugh. Unless they made him more interesting.
Anyone from Halo Wars returning to die wouldn’t affect me too much.
If the Arbiter died, I would be pretty traumatized. He was awesome.
If a Spartan from the expanded universe (Eric Nylund’s books, Grey Team, Naomi, etc) died, it would be upsetting to a varying degree. Fred/Linda/Kelly/the rest of the surviving Spartan 2s dying would be very sad, especially if MC witnessed it. I might be sad if Halsey died, depending on how The Thursday War characterizes her. She was pretty dislikeable in Glasslands.
If 343 introduces a new team of Spartans and manages to develop them well and make players genuinely care for them, I’ll probably be badly hit if they died.