He leads the Nighloks from his ship on the Sanzu River and seeks to cause the river to flood with the tears of humans, using the Nighloks to make them cry, allowing him to enter the world of the living and take it over. He is weaken ar onw point and submerged deeper in the river, letting Serrator take control. He comes back and becomes stronger and rises to the surface. He beats up the Rangers but is weaken and needs to sleep it off.
Thanks to Dayu he rises out again and uses part of Dayu's human life energy as a shield against Lauren's sealing symbol. Lauren's sealing symbol failed and Xandred brought the Sanzu River up to the surface and had a large Mooger army attack the city. The Ranger's plan, with Jayden leading them, was to destroy Xandred instead of sealing him. Xandred destroyed the first disc Lauren made of her Symbol Power but couldn't with the second as Jayden used it in Shogun Mode to defeat him. Xandred was destroyed with the power of all the zords and all the Rangers' symbol power.
Dayu is an innocent woman madly in love with Deker long ago. When Deker was near death because of an accidental fire, Serrator came to Dayu with a deal. Dayu agreed to the deal but Serrator betrayed her by having Deker forget who she was and made her into a nighlok. She joined Xandred because she claimed him with playing her harmonium, a stylized shamisen. Dayu left the ship with the prescence of Serrator and wandered the surface with a little Furry Wart. She tried to make Deker remember and tried to stop him in his final battle. With him gone, she lost all hope and decided to help Xandred, having him destroy her. Xandred used the last piece of her human life as a shield.
Octoroo is one of Master Xandred's two followers, an eldery cephalopod-headed figure with a staff. He tried to open a portal through a well by having a Nighlok steal toys from children. He once came out to the surface to poison Jayden and ended up fighting Antonio. He has long tentacles he can use to wrap around people and electrocute them. He then uses half of his life to power up the Nighlok of Gigerox and give him a deadly third life. He was last seen in the ship as the Sanzu River was drawn back.
The Moogers are Master Xandred's footsoldiers, armed with swords and bows. Some of them fly and others come with purple or brown pants, depending on the situation. They are able to become giant and fight zords. At one point, they were armed with cannons. When Professor Cog came to their dimension, the Grinders became motorcyles and the Moogers rode them.
Deker is a mysterious Nighlok swordsman that can assume a human form. Considers Jayden to be his greatest challenge for his sword Uramasa and tells him he is 'dark' like him. Deker was once completely human and near death as his wife Dayu made a deal with Serrator to bring him back. But Deker was cursed to be half nighlok and forgot who she was. Even as much as Jayden defeated Deker, he would return. Jayden destroyed Uramasa and Deker wanted Serrator to fix it. Deker waited a lot and in the mean time was given a blade but it wasn't the same for Deker. Ultimately, Serrator revealed he needed Deker as a half-human in a plot to open a large long crack in the world to bring out the Sanzu River. With Uramasa back, Deker cause not to go along with the plan. Deker did fight Jayden in one final duel but it was Kevin was defeated him. He was able to rest in peace for once.
One of Master Xandred's general's with six slitted eyes and a ricus grin. He was responsible for cursing Deker and turning Dayu into a Nighlok. Serrator tried to overthrow Xanderd and betrayed him more than once. Serrator's ultimate plan that took over years was to create Deker in order to make a crack in the world to open the Sanzu River. Serrator has his own followers who are stronger Nighlok, driving the Rangers to unlock Super mode. Serrator cursed the people of the island Monalua with ash that made them depressed and fear everything. Serrator later introduced blasters to the Moogers in order to combat the Rangers' swords but was bested with the Bullzooka. Serrator's ultimate plot that involved Deker was stopped with Deker refusing to do so. Bulk and Spike even clogged up one of his geysers. Serrator was destroyed by the Rangers and their zords.
The Spitfangs are foot soldiers that resemble skull-like, eyeless, crocodile-heads with arms and legs. They can breathe fire quite readily. Like the Moogers, Spitfangs can be enlarged to fight the Zords. Each Spitfangs comes in two different colors Gold & Blue.
The Papyrox are giant monsters created by Serrator, who carves out their shapes from a piece of paper. The Papyrox are considered to be stronger than the Moogers and the Spitfangs. Some versions of the Papyrox wield double-bladed swords.