The first boss battle in Stone Shard puts you to the test. You meet them at the end of the prologue after learning the basics of how to play. During this, you and your group of adventurers have been captured by cultists who use the power of a Stone Shard, and it is you who can escape to save those who survive. Now at the end you face off against the Cultist leader, and the game doesn't let go of you, which is the rest of the game when it comes to healing, reading your map, and saving.
First stage
During the first stage of the encounter, the Archon summons a shield for protection. You don't have to worry about it just yet. What you need to worry about are the two bronze statues on either side of the shield. The one on the left produces small jets of blood under you that explode, covering the area of blood you need to dodge. He also casts ungodly spells at you which you curse and cannot escape. The statue on the right summons the undead from the massive pile of bodies and heals them. Of the two, you might want to go for the one on the left first due to the damage it does, but both are good options to choose from.
Run to the statue of your choice and start damaging it. If an undead comes to you, take care of it and return to the statue. If you look small, the blood particles jump from the ground to a safe tile. These are the jets of blood from the statue on the left. Once you've taken down one of the statues, they should stop performing attacks and abilities attached to them, and the Archon offers a small portion of dialogue. Go to the other statue and do the same everywhere, dodging bloodstains or fighting the walking dead that approach you.
Second step
After taking down both statues, the Archon transforms into a massive bat. As a bat, the Archon deals a large amount of damage. He has two notable attacks: the Bestial Charge and the Ghost Bats. When the Archon launches either of these two attacks, you should see a preview of the attack's destination. For example, when he's doing the beast charge, you should see a little purple line on the ground where he's going to attack. You want to get out of the way of this attack, and if you can aim it, try to line it up so that it hits an object in the room, like a wall or one of the benches. Ghost bats are harder to dodge and do a lot of damage.
The Archon's other abilities are a basic attack that you need to be in melee range for him to land, a jump to create distance between you and him, and corpse devour. The ability to devour the corpse makes this battle exceptionally difficult as the Archon can go to any of the seven corpses in the room to eat and heal them. You don't have too many options here when fighting the Archon to prevent healing except to hit him regularly with whatever attacks you have.
Weapons and spells to use
Your best option is to keep your distance from this creature. Melee attacks do massive damage, but if you get too close, the Archon can hit you pretty hard with his abilities. You want to stick with using a bow and arrow, and all the ranged spells you can acquire at the start of the game. If you can increase your accuracy, the bow can deal a considerable amount of damage against the Archon, especially if you critically hit him. You can increase your chances of doing a lot of damage with the ability to aim. If you pair a bow with daggers and have passive hands of the dagger passive ability, you can switch to your bow without losing a turn.
For those who prefer to use a melee weapon, you might want to rely on a fat sword or a sword and shield. A great sword can do some serious damage, but you expose yourself to being hit hard enough, which is a tradeoff. But, if you use a shield and a sword, you might be able to last longer against the Archon, since you can't do as much damage. However, using the shield boost ability can help against some of Archon's massive attacks. Try to use the fire barrage spell when the Archon is at a distance large enough to compromise his health.
When you face the Archon, you will find a challenge. But, when you beat him, you're ready to start playing Stone Shard and choose your character to try out in the game's open world.