Ancient Wyvern Dark Souls III Guide
Last update: 01 June 2016
This boss battle is unconventional in that the Ancient Wyvern can be killed quickly and painlessly by jumping down on it from above. As a result, the boss dies immediately, regardless of the weapon you are currently wielding. However, if you do not want to make things too easy for yourself, you can get a weapon that deals damage from lightning and frost, because the boss is more vulnerable to them. You can then stand still in the spot in which the Wyvern arrived and try to remain under the boss's belly for the entire battle. You will be dealing relatively low damage, but you should be relatively safe from its attacks, at the same time. (the Wyvern will mainly be trying to crush you). Both from this spot, and from the one from which you can jump down onto the wyvern, it is easy to deal damage with bow.
If you do not decide on the extended fight with the boss, walk around it as soon as it appears in the arena. Then, run towards the ruins on the left. Along your way, deal with the shielded opponent quickly and then with two more. A bit ahead, climb up the stairs and watch out for two more opponents who jump down behind you. A bit ahead you will run into two more opponents. You will then be right in front the bridge.
Wait for the moment at which the Wyvern stops attacking (it can be breathing fire in that direction) and cross the bridge running. Note the opponent firing projectiles at the other side. He is accompanied by an enemy with axe that you can find a little vexing - if you have cleared the previous are, you can make him follow you across the bridge and defeat him while outside of the reach fire. If you have not defeated the enemies and they are tailing you, simply run around the opponent, do the same in the case of the next one (the one before the mist) and simply climb the ladder.
Walk a bit ahead and hide behind the wall, if the Wyvern breathes fire towards the platform you are standing on. Up ahead, jump down and jump down again, onto the wall of stone. Once you get here, there is nothing in your way and you can attack the Wyvern with, e.g. the bow. However, if you are here to perform the "1 hit kill", wait until the boss stops attacking. As soon as you see the head right above you, jump down in its direction and perform a jump attack. If you perform it correctly, you kill the boss instantly.
Remember that jumping down is not enough - you have to attack while up in the air, thanks to which you land the deadly blow. Otherwise, you drop down and die - while returning to that spot, you can run around all of the opponents, if only you run fast enough and do not stop for anything, especially on the bridge. After the battle, you can return here and collect all of the items that you have missed.
Reward: Dragon Head Stone, 70 000 souls
Location: Archdragon Peak