Ruin Sentinel
The Ruin Sentinel is a Boss found in The Lost Bastille area of Dark Souls 2. There are three Ruin Sentinels, large knights that use polearms to attack the player.
How to Beat the Ruin Sentinel Bosses
The sentinels are very weak to Lightning. They will also do some additional damage from Magic attacks.
Melee Characters
This fight can be tricky no matter what you play as. The reason for this is that after you kill the first sentinel, the other two activate and you will have to face both at the same time, which is never a great thing in Dark Souls 2. When dealing with just the first one, stay on the platform you initially land on. Keep your shield up at all times and constantly circle around the boss on his left side, away from his weapon. Their attack patterns are pretty obvious, and you will find clear opening to attack after their three hit move, or their lunge then swipe forward, which will then leave them open.
As mentioned before, after dealing with the first, the other two activate. At this time you should jump down and prepare for a drawn out battle. Melee characters are going to have to pick and choose their shots very carefully here, as opening up to hit one of them will leave you vulnerable to being hit by the other sentinel. Ranged items like throwing knives or magic pots are a huge plus here as you can pepper the bosses with damage as they follow you. Patience and careful strikes will eventually lead to victory.
Ranged Characters
Casters and archers will have a slightly tougher time with the first sentinel, as the area to deal with him is smaller. Keep your shield up and roll often, although try not to fall off the ledge. Miracle players will find these three bosses to be quite easy as they are quite weak to lightning. After killing the first, jump down and start slinging spells at the other two. The bosses have a few gap closing attacks, so make sure to time your shots correctly, but overall your experience should be easier than that of a melee characters.
New Game Plus
NG+ version of the fight below! (Solo - No summons)
Video: Defeting the Ruin Sentinels