Watching the last Unicorn episode (19) when best Onee-san's dies ( I wonder if it would be spoiler since the OVAs have been available for a long time, but...) and noticed how her Death reminded me of the original Gundam novels and (NOVEL 0079 SPOILER, but it's not canon, read the novels to understand the context)...
Anyway, sure we got a few death's where the dead character returns to mess up with the villain, tons in Z, not as many in ZZ though, but all of them were either a "First love" like Four (Fa is arguably the heroine in the show), while others were absolute secondary like Sarah, Emma, Katz (the epitome of useless), Rosamia, etc.
But it's not always that someone akin to a main character (support) dies leaving important after-death messages for everyone, from "You are not alone" to "You are being targeted (by a Colony Laser)".
This however is what happens to Amuro, after killing Challia Bull and noticing that he was wrong and went Berserk (he was doing exactly what Char wanted to avoid, which was turning a Newtype into a weapon), he was shot by a Rick Dom piloted by a comrade of both Challia and Char (can't remember his name) who was keeping the Pegasus at bay so that the Gundam pilot and Challia would be able to talk, but with those results, he got too afraid of the White Devil and shot him as he was not moving anymore. But with his death, he was able to talk to everyone, telling everyone to follow Char's plan, and not to give up, properly making Char, the antagonist, into a new powerful ally.
And as we know, Riddhe also hears the voice and turns into an ally again, and everyone avoids a freaking beam from behind, and also some great support messages for the people that needed it.