Gayle Gossip is a reporter who Dareth has a crush on, though it wasn't reciprocated for a while.
In Season 9, Dareth came across her and a cameraman being attacked by grunts of the Sons of Garmadon and ends up saving her from the thugs by tripping on a rock and accidentally defeating them. When Gayle asked him who he is, he calls himself her number one fan and leaves while she fawns over him.
Dareth first met them while pretending to be a great master in fighting but they saw through his acts. The Ninja soon saved him from pirates and he apologized for ever doubting their skill and soon came to idolize them as well sought to join him by being the brown ninja. In later seasons, he continues to be there for the ninja who are sometimes annoyed by him but let him help. Though he can be bumbling and a foil to the ninja, Dareth proves himself to be a loyal friend and does manage to help them out such as helping the ninja with the stone army, aiding in escaping Chen's captivity, and helping in the resistance. Due to these acts, the ninja see him as a good friend and often ask for help in some situations.
During Season 9: Hunted, Dareth was sad when he believed them dead though was happy to learn they were alive. After the ninja return in Green Destiny, Dareth was extremely happy to see them again and announced their return. Once the city was saved, Dareth was honored as a hero along with the ninja.
Dareth and Lloyd get along fine, even though he is put off by the latter's attempts to show off. Dareth has helped Lloyd and the ninja by providing shelter from the resurrected Garmadon and providing assistance in the resistance.
Like the other ninja, Lloyd sees Dareth as a good friend and Dareth thinks the same of him, though Lloyd can still be annoyed by his antics but sees he's only trying his best and cuts him slack. This was seen in "Green Destiny" where Lloyd was encouraged by Dareth's words to keep fighting.
He and Nya get along well, though she is put off by his tendency to showoff.
In Season 4: The Tournament of Elements, he accidentally travels with her to Chen's Island, much to her annoyance. However, Dareth had proved himself helpful as his talent in the art of disguise aided Nya in infiltrating Chen's palace and finding out his plan. Nya was amazed by his acts and grateful to him for his help as she was able to find her friends. They later took part in fighting off Chen's army in the Corridor of Elders.
In later seasons, Dareth continues to help Nya and the others, such as providing them shelter from the resurrected Garmadon and helping her in the Resistance. Dareth sees Nya as a good friend, while she thinks the same of him but she is still annoyed by his antics but sees he's trying to help and cuts him slack.
After Garmadon was defeated, Nya invited Dareth to be cheered on too, due to his major help in saving the city. This showed she respects him in spite of his faults.
They may not interact much but Misako and Dareth get along and may be friends.
In Season 2, Dareth picks up the Helmet of Shadows before Misako can, allowing him to control the Stone Army.
In Season 7, Dareth wants the Samurai X suit for himself, but Misako said it was supposed to go to the Samurai X Cave where it belongs. Time skips a minute and Misako is holding the suit while Ronin is on Dareth's back.
During Season 8, he allows Misako and an de-aged Wu to stay in his apartment after Garmadon is resurrected as a villain.
In Season 9, she is appreciative of him continuing to aid her and the others while hiding from Garmadon's forces
They have not had many interactions, but they get along and may be friends.
At the end of Season 4, when he overheard her telling Kai that she was taking over her father's noodle business, he quickly begged her if they'd put the Puffy Potsticker back on the menu. She kindly replied that she will put the item back while he was happy with her answer by calling it right with the world.
In Season 9, Skylor and the Elemental Masters save Dareth's group from the Sons of Garmadon and soon formed The Resistance. Dareth and Skylor ended up being the last remaining allies of Lloyd and Nya after the rest were captured. Dareth even expressed concern for her after she was poisoned by Garmadon's power and tended to her.
The two barely interact but appear to be on good terms, as Dareth goes to him for trophies for achievements he hasn't earn to make himself look good.
In Season 7: The Hands of Time, Dareth ends up breaking Ronin's leg though he apologizes for his blunder and tends to him to make up for it.
The Stone Warrior General Kozu holds a grudge against Dareth for his partial role in defeating The Overlord and taking over the Stone Army. In Day of the Departed, upon being resurrected Kozu personally tried to kill him. When confronted by Kozu, Dareth was horrified to see him again and ran to get the Helmet of Shadows as the villain chased him. After Dareth obtained the item, he defeated Kozu again by once more using the helmet and turned the warriors Kozu used against him.
Sons of Garmadon
They often hung at his business Laughy's, often terrifying potential visitors. He was relieved they were defeated by the Ninja but dismayed after a resurrected Garmadon freed them and they took over the city.
The Sons of Garmadon thought little of Dareth and bullied him for his food, while stating he wasn't a Ninja. Mr. E even tried to attack him but Karlof saved Dareth and joined The Resistance.
At one point, they bullied Gayle Gossip and Dareth intervened on her behalf. They mocked Dareth's speech and taunted him on his lack of skill, though Dareth's clumsiness ironically allowed him to beat them and save Gayle, to his joy.