Afflicted Graverobber, Ancient Soldier Varg, and Cerah the Old Explorer

 are a trio of bosses in Dark Souls II. They are found in the Crown of the Sunken King DLC.

Summoning
There are two NPC phantoms available to be summoned at the start of the Cave of the Dead. They are named Rapacious Andrei and Ruined Aflis.

Strategies
It is best to take care of Cerah the Old Explorer first, as he will shoot the player constantly with a Dragonslayer Greatbow. He is very agile and will pull out an Estoc if the player gets close. He wears Lucatiel's Mask with the rest of the Thief Set.

Ancient Soldier Varg is by far the hardest to topple of the three enemies. He wears full Havel's Set and wields the Dragon Tooth with Havel's Greatshield. Should he be the last one remaining, he will use an Estus Flask.

The third part of the trio is the Afflicted Graverobber. He wears the full Alva Set and dual wields Berserker Blades. He causes heavy bleed build-up and is very dangerous if he catches the player in any sort of stunlock.

Trivia

 * Varg and the Afflicted Graverobber wear the armor sets of people who are supposedly dead.