Reploids are mechanoids made up of "metal panels and tubing" with a symbol that appears to read "Dr. W" on their chest. depicted only in Blood of the Chozo. They have been encountered by Dr. Vincent, who was brought to his home at the ruined moon of Oztaki by the reploids Achilles and Ulysses, pilots of a mile-high Chozo Statue.
- "Dr. W" likely refers to Dr. Wily of the Mega Man series, who signed his robots similarly.
- The Metroid series has its own "Dr. W" since the writing of this story, Doctor Wells.
- The first crossover between Metroid and the Mega Man series occurs in Super Smash Bros. for Nintendo 3DS and Wii U, in which Samus and Mega Man appear together as playable characters, alongside stages and other content from their respective franchises.