Found only in the original Marathon, the Alien Energy Converter is a device whose true purpose is shrouded in mystery.
At one point during the Pfhor assault on the UESC Marathon, Durandal tells the player to retrieve the Alien Energy Converter from a specified location, explaining the S'pht have provided it and that it will allow the player to "slay more Pfhor.
If the player attempts to leave without first acquiring the device, Durandal says he could just let him leave without it, but that he would be sorry later.
The level cannot be successfully completed unless the Alien Energy Converter is found.
- After retrieving the Alien Energy Converter, Durandal explains the player will be going "farther afield" and the device is somehow necessary while on board the Pfhor ship. The most likely explanation would be to enable the player to interface with alien shield recharges and Pattern Buffers.