E-103 Delta

E-103 Delta (Ｅ－１０３ "デルタ"), or E-103 "δ", is the fourth of the E-100 Series robots constructed by Dr. Eggman, coming behind E-100 Alpha, E-101 Beta, and finally E-102 Gamma. He appeared in Sonic Adventure, in which he plays a minor role in E-102 Gamma's story as a boss. He resembles the other E-Series robots, except that he is silver and blue in color. He has the dual rocket launchers like Beta, but in addition it has a jetpack built into itself for short range flight.

History
Along with his brother E-Series robots (E-102 Gamma, E-104 Epsilon, and E-105 Zeta), Delta was sent by Doctor Eggman to retrieve Froggy, who had swallowed a Chaos Emerald. When Delta failed to locate the correct frog, Eggman banished him from the Egg Carrier along with Epsilon. He stares at Gamma as he is teleported away, but it is unknown whether any feelings were stirred in the robots.

It is later revealed that he was abandoned at the Windy Valley. Gamma later tracked Delta down, intending to "rescue" Delta by destroying him, thus releasing the animal trapped inside him. The two brothers battled, and Gamma emerged victorious. Delta was destroyed, and the animal inside him was freed.

Powers and abilities
At first, Delta is a clone of Gamma, with just a target locator scope, an arm cannon and a hand. After being discarded by Eggman without his scope, he inherits E-101 Beta's twin missile launchers in place of his arm cannon and hand and a Jet Booster.

Boss guide
E-103 is quicker on the draw than E-101. Use the open space to keep your distance and stay out of trouble. If you don't let Delta get on top of you, you'll have enough time to target and destroy its homing missiles. After you take out any threatening missiles, lock on to Delta and fire!

Trivia

 * After Delta fails his mission and is banished to Windy Valley, he takes on the same design as the unmodified E-101 Beta, though retaining his colors and numbering
 * Despite his lock-on ability in his upgraded form, Delta visibly lacks a targetting sight like Gamma.
 * His Jet Booster seems to let him fly for a short amount of time, instead of hovering like Gamma's.
 * Although he no longer has a functional forearm due to his missile upgrade, a mirror reflection of Delta's original forearm still appears on his front skirt plate. This is due to the fact the reflection is an actual painted image within Delta's textures, which was repurposed from Gamma's textures.
 * There is a glitch where right before the boss fight; if the player was to jump of some high elevation and fly to the left, Gamma will land on a rock sticking out of the mountain, allowing him to "snipe" Delta.