Complete the indicated task to unlock the corresponding skin for Multi-player mode.

Anthony Carmine: Complete Act 1 in the original Gears Of War (have any Act 1 achievement unlocked from that game).
Dizzy Wallin: Complete Act 1 in Single Player mode.
Flame Grenadier: Complete Act 4 in Single Player mode.
Kantus: Complete Act 2 in Single Player mode.
Lt. Minh Young Kim: Find 10 COG tags in the original Gears Of War (have the "Time To Remember" achivement unlocked from that game).
RAAM: Defeat RAAM in the original Gears Of War (have the "A Dish Best Served Cold" achievement from that game).
Skorge: Complete Act 5 in Single Player mode.
Tai Kaliso: Complete Act 3 in Single Player mode.