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Sonic Wiki Zone
Sonic Wiki Zone

This frog's the one we want!

— E-103 Delta, Sonic Adventure

E-103 (E-103 Ī 103?), codenamed δ or Delta (デルタ Deruta?), is a character that appears in the Sonic the Hedgehog series. He was the third E-100 Series robot created by Dr. Eggman during the Chaos incident to aid in the destruction of Station Square.[1] Tragically, however, after a mission failure, Delta was remodeled and banished to Windy Valley, where he was destroyed by E-102 Gamma.[2]


E-103 Delta was a humanoid robot colored in blue and white. He possessed no neck, his head and torso coming together in an almost ellipsoid shape. His torso was blue with a wide and white vertical stripe down the middle and possessed a head light with a hexagonal gray frame on the right side. He also had gray mufflers surrounding the pelvis area and had the number "103" painted in white on the right of his large vertical stripe and the left side of his rear. His head meanwhile was small and platform-like with a yellow shade and green cylindrical eyes. He also had a Jet Booster hovering behind his neck.

Delta's shoulders were black vertical cylinders. Attached to each of them were Delta's arms, which were long and designed with two joints; each of Delta's forearms were designed as blue gun barrels. Originally though, his left arm held a black-gray blaster while his right arm had a tri-digited hand with two points of articulation on each digit. Also, Delta's upper arms were blue, while the parts between his upper arms and forearms were gray. Delta also possessed two long and inverted legs with five points of articulation and large, black feet with two sharp toes and roller wheels on the heels. The upper sections of his legs in particular were blue while the rest of them were gray, except from his calves, which were thick and blue.


Sonic Adventure[]

Dolphin 2015-10-14 18-43-43-795

Delta being discarded, from Sonic Adventure DX: Director's Cut.

In Sonic Adventure, its enhanced port Sonic Adventure DX: Director's Cut, and the 2010 remaster, Delta was created as the third unit in the E-100 Series of shooting robots in order to aid Dr. Eggman in his agenda to destroy Station Square and build Robotnikland on its ruins.[1] At some point, E-103 was able to become part of the Egg Carrier's crew, alongside E-102 Gamma, E-104 Epsilon, and E-105 Zeta. There, Eggman tasked them to retrieve Froggy, who had swallowed a Chaos Emerald. However, Delta failed to locate the correct frog, and the doctor remodeled him, Epsilon and Zeta. Nonetheless, they were all banished from the Egg Carrier afterwards.[2]

It was later revealed that Delta ended up in the Windy Valley.[2] Gamma later tracked Delta down, intending to "rescue" him by destroying him, thus releasing the Animal trapped inside him. The two battled, and Gamma emerged victorious. Delta was destroyed, and the Parrot inside him was freed.

Powers and abilities[]

As part of the E-Series, Delta was a very advanced robot that was developed to advance weaponry.[3] After being remodeled, he also had twin missile launchers and a Jet Booster.





E-103 Delta is the second boss in E-102 Gamma's storyline in Sonic Adventure, its enhanced port Sonic Adventure DX: Director's Cut, and the 2010 remaster. In Adventure Mode and Trial Mode, he is fought at the end of Windy Valley. He is only encountered with Gamma.

Boss guide[]

Delta is a relatively simple boss, using the same attack patterns as E-101 Beta. However, it should be noted that Delta is quicker on the draw than Beta.

In gameplay, Delta will stay in one place and shoot homing missiles at the player, or take to the air with his Jet Booster. Use the open space to keep the distance and stay out of trouble. If the player does not let Delta get on top of them, they will have enough time to target and destroy his homing missiles. After the player take out any threatening missiles, lock on to Delta and fire. After landing five blows on Delta, this boss will be defeated.


Title Artist(s) Music Length
"Heartless Colleague ...Boss: E-Series Targets" Jun Senoue, Yoshitada Miya 1:25



Sonic Adventure Boss 11 - E-103 Delta

In other media[]

Archie Comics[]

Main article: E-103 Delta (Archie)

Sonic X[]

Main article: E-103 Delta (Sonic X)


  • Despite his lock-on ability in his upgraded form, Delta visibly lacked 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.






  1. 1.0 1.1 "All Star Cast". Sonic Adventure Tokyo International Forum Unveiling Booklet. 22 August 1998. p. 9.
  2. 2.0 2.1 2.2 "E-102"γ"" (in Japanese). ソニックアドベンチャー オペレーションガイド. SoftBank. January 1999. p. 122. ISBN 978-4757203006.
  3. "Dr. Eggman in... My Greatest Invention". Sonic the Hedgehog: Rival Edition. Tomy. 2017.

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