And a boss fight is what he gets!
The huge stone door opened into an even bigger chamber. The first thing to notice was the enormous altar on the other side of the room, in front of the door. The room itself was dimly lit by 4 chandeliers close to the four corners of the room, there were also torches all around on the wall. Two wide red carpets crossed in the middle of the room, with their ends in the middle of every side of the walls.
Also in the middle of the room there was a huge skeleton of a bipedal, gorilla-looking monster with runic engravings all around it on the ground in a circular manner, probably written by blood. The beast stood approximately 5 metres in height, back when it was still alive.
As Zora entered the room he already prepared 3 lightning orbs and a 2 ice ones. His absolutely limit at that time was 10 orbs of the same type, 5 orbs if there are 2 different types, and 3 orbs if there are 3 types. He was also able to make 5 different orbs, one of each.
When he noticed the skeleton with the engravings around it, he cursed, and rushed to dismiss the lightning ones and summon up to 10 ice orbs. Even though they are made up of 2 elements, or are tier 2, as its called in the magician slang, it doesn't increase their mental upkeep, but it takes substantially more time to summon them. He needs around 3 seconds to pull one tier 2 orb together. This means half a minute for 10, which he already had 2 of.
At the same time when Zora started redistributing his orbs, the skeleton of the beast started moving, as the engravings around it sprung into action with fiery red light. If Zora had the time, he would've absolutely marveled at the light show, but he was too busy cursing and focusing on the ice element to care.
He only finished with 4 orbs by the time the beast started rushing towards him. This, Zora noticed, so he charged up every orb he already had and started throwing huge ice spears at it. Its always advised to form the spear with the orb in the middle of it, that way, when it is forming, the orb can use the maximum output potential. Also, there are two ways one can fight with an ice spear.
One, when the ice spear is thrown, together with the orb, one either dismisses the orb or calls it back, whichever is more time saving. This way the orb is only in use until the ice spear is launched, and the spear is only used for its potential kinetic damage. Thus the caster can reuse to orb to keep fighting.
The other way is to leave the orb inside the ice spear and keep up its ice production, actively freezing whatever it is in contact with. This way the freezing effect of ice is kept up, but the orb is not usable for further attacks, until its recalled or dismissed.
Knowing this, Zora first tried to use all the ice orbs to generate one massive ice spear. It took 2 seconds to form with 6 orbs of ice working together. All the while the enormous frame of the skeleton beast was banging loudly on the floor as it rushed towards him. By the time the spear was finished the beast was about to jump on Zora's head, so he launcher his attack right away. The beast, seeing the threat, instead of jumping at its prey, it decided to dodge by jumping to the side.
Now Zora had no weapon to attack with, the beast was still recovering from the hasty dodge, but was close enough to be an immediate threat, so Zora had to dismiss 2 orbs of ice and summon a wind one. With it he was able to fly around, not very agilely though. Or fast at that.
Zora was already in the air by the time the beast recovered and continued rushing towards him. He was trying to slowly move away while also forming smaller ice spears that he threw at his enemy
The beast had to slow down and be careful about his positioning. He either had to deflect the ice spears aimed at its head, or dodge them. Either way he was unable to sprint to kill Zora.
This war of attrition was seemingly bad for Zora, but he realized that this skeleton had no core either, meaning he was able to use magic directly on its body. The skull, unfortunately, was too strong to crush with pure mana. Maybe the one who made the skeleton reinforced the skull, considering that is it's the only weak point. But even though pure mana doesn't work, he had an idea.
He dismissed two more ice orbs, and summoned two water ones in an instant, as tier 1 orbs were extremely easy to use. With the water orbs he started drenching the skeleton, all the while he kept throwing ice spears, all the while the enemy was getting closer.
At one point, when the beast got close enough, it threw all caution aside and rushed straight at Zora with a massive jump. This was the exact moment Zora was waiting for, though. He stopped with the attacks and focused on dodging.
When the skeleton-gorilla flew past him with alarming speed, he turned around and instead of forming ice spears, he made the orbs fly close to the skeleton's body and started freezing all the accumulated water on it, all the while he kept spraying with the water orbs.
It barely needed a few seconds for the space where the skeleton's joints were supposed to be, to freeze over in a thick layer of ice. The beast tried to shake itself free of the forming ice, but it wasn't enough, Zora's magical throughput was too much for it. Soon the beast completely stopped moving, its limbs got locked into ice.
When that was done Zora landed, dismissed all orbs except ice, summoned a few more, to have exactly 5, then used them to form the biggest ice spear he can make above the skeleton's head. Next he just had to let go of it, the sheer mass of the spear was enough to crush the skull underneath it.
With its head destroyed, the skeleton ceased all functions and turned back into simple remains it was supposed to be.