Helios is the guardian of Elysia's Leviathan. This mechanoid looks like a small round sphere with four tentacle-arm like appendages. He is the prime robot of a group of Swarmbots, also inhabiting the Leviathan. Helios has seven forms. All but the final form are invulnerable, and he only takes this form after being hit in his other forms many times.
The first form he appears in is his neutral form. He has a large sphere of Swarmbots that surround him and act as a shield. He will just float in the middle of the arena. He will change into any of these:
Sphere: After arranging the Swarmbots into a large sphere, he will fall to the ground and try to roll at Samus, who can strafe out of the way and fire at the core in between the Swarmbots. "Helios is using the Swarmbots to form a fast-moving ball of energy. Avoid contact with the sphere."
Disc: He will arrange the Swarmbots into a large disc which has five weak points, which must be shot all at once with the Seeker Missiles. If he remains in this form for an extended period of time, the disc will increase in size, making it harder to dodge. The disc can also charge up and fire a large beam of Phazon. "Helios is using five seperate bots to maintain his form. Destroy them simulatenously to stop his attack."
Beam Array: He will arrange the Swarmbots into many small groups that will in turn charge up and fire at Samus. The glowing groups can be destroyed before they fire. "Helios is charging each group of Swarmbots for a powerful attack. Overload their energy to damage them."
Tornado: He will arrange the Swarmbots into a large tornado with him at the base and start spinning toward Samus, sucking her towards it to deal contact damage. Morph Ball Bombs and the Hyper Ball can attack this form.
Humanoid: Helios will split the Swarmbots into four groups which will become "arms" and "legs". These will sometimes fire giant orbs (that create a small, horizontal explosion) at Samus. The legs also can make a strong shockwave. The joints at which the limbs are connected can only be damaged when the corresponding limb is preparing to strike; once Samus destroys each of these joints, Helios will collapse. "Helios's bots have assumed a humanoid form, but the arm and leg joints appear to be weak."
Exposed: Once he's been hit enough in the previous forms, he will open his core and dispel his Swarmbot backup. His mechanical arms will extend blades and he will charge repeatedly at Samus, who must go into Hyper Mode and fire her Hyper Beam into the front of his core to deal damage to the mechanoid. Note that coming into contact with the blades can disrupt Samus' visor, leaving her open to more attacks. "Helios's outer shell is open. Core is exposed and vulnerable to Phazon-based attacks."
"Helios's exterior armor is well shielded, but still vulnerable to Beam weaponry. Inflicting enough damage will cause him to overheat and expose his Phazon-enhanced core. This core can be overloaded with Phazon-based energy. Destruction of the core unit should prove fatal, but is difficult to achieve. Target is the prime bot of a large group of Swarmbots, all of which have been energized by Phazon. Helios will use the Swarmbots for both offensive and defensive measures. Assuming different formations will allow for various forms of attack."
Interestingly, Helios' scan names him as a male despite being a mechanoid.
Since Helios is the commander of so many Swarmbots and seems to connect with them, it is possible Helios is either a corrupted Swarmbot or a corrupted version of a sort of Swarmbot commander, similar to the Steamlord in comparison to the Steambots.
He appears to be partially organic, as evidenced when damaged or at the beginning of the fight.
In Greek mythology the sun was personified as Helios (pronounced /ˈhiliˌɑs/) (Greek: Ἥλιος, Latinized as Helius). Homer often calls him simply Titan or Hyperion, while Hesiod (Theogony 371) and the Homeric Hymn separate him as a son of the Titans Hyperion and Theia (Hesiod) or Euryphaessa (Homeric Hymn) and brother of the goddesses Selene, the moon, and Eos, the dawn. The names of these three were also the common Greek words for sun, moon and dawn. The best known story involving Helios is that of his son Phaëton, who attempted to drive his father's chariot but lost control and set the earth on fire.