Metal Knuckles

Sonic Universe #37 (First appearance)

Sonic The Hedgehog #'s 242-246

Last updated: March 13, 2013

Krudzu

Sonic The Hedgehog #'s 1 (First appearance), 57 (Flashback), 241, 244-246

Free Comic Book Day 2010

Last updated: March 13, 2013

Titan Metal Sonic

  

Also known as Metal Sonic Kai

Knuckles Chaotix Special (First appearance)

Sonic The Hedgehog #'s 231, 241, 246 (Titan Shard in Off-Panel)

Sonic Universe #37 (Cameo), 65 (Off-Panel)

Last updated: June 21, 2014

Harvey Who

Sonic The Hedgehog #16 (First appearance), 233, 235, 237-238, 240

Sonic Universe #41-44

Last updated: February 6, 2013

Mecha Sally

Note: This character is the roboticization of Princess Sally Acorn

Sonic The Hedgehog: #'s 29 (First Appearance), 230-234, 235 (Cover only), 236-239, 247, 251 (Flashback), 252 (Flashback/Off-Panel), 256 (Flashback)

Sonic Universe #37-40, 50

Mega Man #26 (Crossover/Flashback)

Last updated: January 17, 2014

Tails Doll

Sonic The Hedgehog #'s 231 (First appearance), 232, 236, 240-241, 247, 252, 265, 267, 275 (Variant Cover), 279

Sonic Universe #49 (Off-Panel)

Last updated: March 11, 2016

Angelus

Also known as Babylon Guardian

Sonic Universe #33 (First appearance)

Last updated: November 8, 2011