Onox is one of two main antagonists from the game Oracle of Seasons. He calls himself the "General of Darkness", and wishes to ruin the land of Holodrum in accordance with the wishes of his master, Twinrova. To do this, Onox has been tasked with the burden of capturing the Oracle of Seasons and submerging the Temple of Seasons. Although Onox appears to be an armored being like an Iron Knuckle, his true form is that of a dragon, summoned from the Dark Realm.
Onox in the process of capturing Din, the Oracle of Seasons.
By capturing the Oracle of Seasons, Din and encasing her in crystal, Onox is able to submerge the Temple of Seasons into Subrosia and throw the flow of the seasons into chaos, resulting in the damage of the land and the weakening of the Maku Tree. To counter these drastic events, Link sets out on a quest to obtain the Essences of Nature, which allow him to enter Onox's Castle on the Northern Peak to face him, and revert his dastardly deeds.
Battle and Ultimatum
After gaining each and every one of the Essences of Nature, Link makes his way to the Northern Peak, where he uses their power to bust into Onox's Castle, breaking the protective barrier Onox had placed upon its entrance to bar intruders. Link faces Onox in two segments, the first in his natural form, using the comatose Din within a crystal to shield himself from Link's attacks. Before Link can defeat Onox, however, he reveals his second, true form to Link, Dark Dragon. Although larger and stronger than anything Link had fought in his journey thus far, Link is still able to pull the plug on the General of Darkness. However, rather than cursing his own fate, Onox mocks Link as he dies, revealing that the Flame of Destruction has been lit, and Twinrova's grand scheme is one step closer to fruition.
If Link has already saved Nayru from Veran's clutches in Oracle of Ages, when Link reaches Onox at the top of the Onox's Castle, Onox will reveal to Link that Zelda is already being prepared for sacrifice, so that Ganon can return.
Onox's Dark Dragon form
Onox deals out massive physical damage with his attacks, so it is in Link's best interest to dodge. His armor also blocks normal attacks with the sword, so Link must use Spin Attacks to get through. Onox's range of attack normally does not reach beyond the Ball & Chain Trooper, but he is also capable of bringing down a barrage of rocks from the ceiling, and summoning multiple tornadoes. Partway into the battle, Onox will summon a frozen Din as his shield. The Rod of Seasons must be used to knock Din away, or Link will be electrocuted whenever he attacks Onox. Despite this, Din, will always drift back to Onox eventually. After Onox is defeated again, he will transform into Dark Dragon. From here, Link must jump onto Dark Dragon's hands, then attack the gem on Dark Dragon's head.
The Gerudo Symbol appears on the chest plate of Onox's armor. This may indicate his connection with Twinrova.
Onox's name is misspelled twice in the Linked Game of Oracle of Ages as Knox. The first time is when Twinrova anounces that the three flames are now lit, saying that the Flames of Sorrow and Destruction were lit by "Veran and Knox". Later, when battling Twinrova, she announces that she will "not fall like Knox or Veran". Curiously, this does not occur in the Linked Game of Oracle of Seasons.
Onox's name is a phonic reference to Onyx, a hard mineral known for its black variety. The characteristics of Onyx could be likened to Onox's strength and dark powers.
Onox bears a striking resemblance to the Iron Knuckles from Ocarina of Time, as they both have heavy golden armor, menacing helmets, and a connection to the Gerudo; However, he uses a flail instead of an axe. His fighting style with the flail resembles that of a Ball & Chain Trooper.
Onox's helmet is somewhat reminiscent of Zant's, as both helmets have a pointy, cone-like shape, cover the entire face, and have a menacing, aggressive appearance.
Dark Dragon is often regarded as one of the hardest bosses in the Zelda series, possibly because he is the final boss/ante-penultimate boss in the game he is in and he is fought in a side scrolling section.
The strategy used to defeat the Dark Dragon, as well as the boss itself, bear a notable similarity to the strategy used to defeat the final boss of the game Mega Man X, Wolf Sigma. As both Oracle of Seasons and Mega Man X were made by Capcom, this may be more than simple coincidence.