Shade the Echidna

Shade is a Marauder who helped steal the last Chaos Emerald from Knuckles the Echidna. Originally, Knuckles was fighting a whole group of Marauders after they destroyed a trap made by Tails. Knuckles fought well, until Shade stepped on to the battle field and knocked him out quickly, though she was impressed by Knuckles. Despite the rest of the Marauders objections, Shade decided to keep Knuckles prisoner after retrieving the Chaos Emerald. Little did she know that as soon as she left, Tails raced for help from Sonic the Hedgehog, Amy Rose and G.U.N.. (StH: #191)

Backround information
The story Shade debuts in called "Invaders From Beyond," acts as a tie-in to Sonic Chronicles: The Dark Brotherhood, as you don't actually see Knuckles getting kidnapped.