That's a Gelgoog, One Year War era, from the Universal Century timeline. Basically, the bad guys would have won the war had they rushed it into production, but they dicked around with stupid prototypes too much and it ended up coming out too late.
And by Grim Reaper thing, I'm betting
Gundam Deathscythe?
__________________
Ah, we are high school boys,
the miserable high school boys.
If we were girls, we could get popular by doing anything:
rock band, jazz band,
karate, kendo, mahjong, cyborg, synchronized swimming...
On the other hand, high school boys are
useless outside battle and sports anime.
But they're recklessly trying to make a slice-of-life anime about us.
Ah, we are high school boys,
the miserable high school boys.