Sergeant E. Monz was a 1st trooper of GFMC Task Force Herakles, who, like the rest of the troops, died in battle against the Dark Splinters. It is unknown how he was killed, but his body was most likely used as a Dark Trooper, which was later destroyed by Samus.

Metroid Prime 2: Echoes Bonus Disc[]

"What's the matter? All I said was that Komaytos look like little Metr—"

Non-canon warning: This article or section contains information that may not be considered an official part of the Metroid series in the overall storyline by Nintendo.

SPC F. Triplette's Trooper Log mentions that Monz has had previous experience with a "killer bug" on Devon III, which he compares to the Splinters. Monz has an unused entry that sheds further light:

Unused Logbook entry[]

SGT E. Monz

Metroid Prime 2: Echoes

Logbook entry

I swear I've seen these bugs before. There was an infestation on Devon III back when I was a green private; it took 2 cycles to cleanse the place. If these are the same bug, we're gonna need bigger guns. Bigger guns, and a lot more guys.

Non-canon warning: Non-canonical information ends here.