Walter Ryan is one of the two playable characters in Metal Slug Advance.
A troubled character that couldn't find his purpose in life, he enlisted in the Peregrine Falcons to train his mind and body and had succeeded in obtaining self-confidence while increasing his endurance through participation in rigorous training courses offered by the Peregrine Falcons. When he discovered that the Rebels attacked the island where he was going to train, he didn't hesitate in advancing and find the true worth he was looking for. After graduating along with Tyra, he became one of the P.F. Squad reserves. He calls his adventurer Mama on a weekly basis.
One of the cards you can get in Metal Slug Advance is Walter's Mama. The card describes her as "One Wild Lady"
In Other Games
He later cameos in Metal Slug Defense, with his appearance being based on his in-game sprites rather than his official art, but he later appears as a playable unit. With the cost of 120 AP and 5,100 HP on level 40, Walter uses the Drop Shot as his main weapon and his punching glove as his close range attack.
His sprites use the light color palette from his home game, making him stand out from the rest.
He makes his appearance as the poster boy of the "Boy's Memories" event, where he is a Pack-Shop unit (now found in the POW Shop). He is able to shoot more Drop Shot bullets than before. His sprites are now in a darker color.
- Either due to palette issues or an error, the inside of Walter's mouth is colored blue.
- Walter's sprites are edits of Marco.
- Unused sprites in Metal Slug Advance show Walter talking to a walkie-talkie. This gets used in Metal Slug Defense and Metal Slug Attack.
- In his appearances in Metal Slug Defense and Metal Slug Attack, his last name is written as Rian instead of Ryan.