These are the relationships of the Dark wizard Clouse.
Chen was Clouse's master.
For decades Clouse loyally served him, as he trained under him, fought by his side in the Serpentine War, and exile. Clouse respected Chen, despite the latter's eccentric nature and always had his interests on mind. Clouse even found his master to be amusing at times, as they shared a laugh over turning the ninja against each other and the imminent capture of the elemental masters.
Despite this, Clouse was not above criticizing his master as he did not hesitate to bring up Skylor's betray when Chen disrespected his fallen pet. Nonetheless, Clouse reminded Chen that Skylor also performed the spell that would transform them into Anacondrai, something Chen hopped on immediately.
After their banishment to the Cursed Realm, they would be situated in cells together. Clouse appeared to stay loyal to him, as he would have to remind Chen he was seeing things. However, Clouse was cutting his cell to get free. After doing so, Clouse had no qualms in abandoning Chen to his fate who would be destroyed with The Preeminent's destruction.
The Serpent was Clouse's beloved pet.
Clouse appeared to have the serpent for decades, as it fought in the Serpentine along with Clouse and was banished with him.
The Serpent was very loyal to Clouse had, as it brought a scrap of clothing that Jay was wearing to Clouse, who used it to identify the Ninja. Clouse was very affectionate, as he caressed the serpent's head as reward for its task. He also enjoyed feeding people to it both for sadistic pleasure and to satisfy its hunger.
Clouse was also devastated at its demise, as he would caress his beloved pet's corpse, assuring his love for it by stating he couldn't have ask for a better pet before swearing vengeance on Garmadon for the Ninjas' actions.
Garmadon is Clouse's former fellow apprentice under Chen. They often trained together as both wanted to earn a place as Chen's right hand. Garmadon's victory over Close is what gave him his title as Lord and would earn him Clouse's hatred.
Years later, the two met again and both were not pleased to see one another but hid their contempt under false pleasantries. However, Clouse wasn't above needling at Garmadon's soft spots, such as bringing up how he swayed his wife to fall for him.
In their final fight, Clouse showed his detesting of anyone related to Garmadon such as his son Lloyd who he stated that one day he would have to fend without his father.
Garmadon fought Clouse once more and the latter attempted to banish him to the Cursed Realm and taunted him on his impending defeat. However, Garmadon was able to escape the spell and send Clouse to the realm instead. Unfortunately, this fight foreshadowed Garmadon's true banishment to the realm.
Clouse sees the Ninja as enemies.
Clouse was in on Chen's plot to steal their powers for the transformation spell, though hid this from his foes. During the tournament, Clouse would attempt to sabotage the ninja but was prevented either from interference by Garmadon or orders from Chen. He also prevented a captive Zane from breaking out, as he knew the ninja were there for him. Clouse was aware they spied on the ritual to drain the Elemental Masters, though was prevented from taking action. However, he took satisfaction when Chen turned the ninja against each other or turn their growing allies on one another. Clouse detested the ninja, notably Lloyd who was Garmadon's son. Clouse also fought Nya (not a Ninja yet) for the spell after she infiltrated the palace.
After Chen gave up his ruse, Clouse took pleasure in hunting them before he fought and defeated Jay who was captured.