Korea participates in a America-Iraq war, backing America up by sending troops to Iraq.

Sehun is the general-in-charge, Luhan... Just one soldier amongst the three thousand.

...

The war comes to an end, America won but the Korea contingent suffered heavy losses because their fight in particular had not gone well, they had been caught up in a desert storm with no preparations in store for what was coming.

Both Sehun and Luhan are survivors, and that's about it. Two survivors. Out of three thousand.