Achilles is an unused prisoner from Metal Slug 5.
He was supposed to be a support character like Hyakutaro, who would cover the players' back after being rescued and run away when the player dies. However, due to SNK Playmore rushing the game, he ended up being unused, as he needed a lot more programming added to his AI to be of any real use.
If the players constantly move around, he'll simply follow them everywhere, trying to keep behind the characters, so if enemies come from both sides and the players are turning a lot, he is rendered useless. Still, his weapon has massive destructive power (an SMG firing explosive rounds) at the expense of only having very short range. He has the inability to shoot upwards, and he cannot distinguish between enemies and destructible objects, like Hyakutaro does.
Unlike other support POWs, he has no unique end tally sprite. The game treats him as a standard POW (worth 10,000 points) with a randomized name and rank in the Recaptured Prisoners screen.
According to the debug levels, this character is only found in an unused arena of Mission 3 (Area 3:9), alongside the Flame Shot (also unused). He appears standing up still waiting for a player to tag him. One player can rescue both Achilles and Hyakutaro in the area, and both prisoners follow the player until the player reaches a new area, dies, or leaves them stranded.
- The name "Glen Achilles" was dubbed by Ragey, the owner of the fansite Metal Slug: Missing In Action. Ragey was among the first to discover the unused POW, and apparently, the name that appeared after rescuing him was "Achilles". Ragey added the first name "Glen" because the character reminded him of an old music teacher of his.
- In Metal Slug: Super Vehicle-001, there is a private that in the recaptured prisoners list is named Achilles.
- Achilles and his partner appear in the PlayStation 2 port's flyer of Metal Slug 5.
- When Achilles is shooting, he uses Marco and Tarma's backward shooting sprites from the first game.
- It is possible that he was intended to be a playable character too, though this is unconfirmed.
- Special Allen Jr. in Metal Slug Attack bears a resemblance to Achilles.