Looking Glass Knight

The Looking Glass Knight, also known as the Mirror Knight, is a boss in Dark Souls II.

General information
The fight against the Mirror Knight takes place at the top of a castle structure during a lightning storm. This boss will use physical attacks against the player as well as using his sword as some sort of "lightning rod" and then launching an electrical blast towards the player.

The knight also has a large shield in the shape of a mirror, and when he plants it into the ground he will be able to summon another player as a hostile enemy to the fight (like the Old Monk in Demon's Souls). This can be done multiple times but it is currently unknown if the Mirror Knight can use this ability as many times as he wants or for a limited number of times.

While fighting this boss offline, he will summon randomly generated AI instead of human players. Also, while the knight is summoning an invader, the players can take advantage of the situation for either attacking the Mirror Knight or for "cracking" his mirror in order to prevent another invasion.

Lore
The Knight serves as Vendrick's lieutenant and before the King's fall and the collapse of his kingdom, would test the skills of warriors who wished to serve in the order of royal knights. Those unfortunate to fail the test met a grisly end and he continues to challenge individuals who cross his path.

Trivia

 * The Mirror Knight resembles the Old Monk from Demon's Souls, as both bosses are able to summon other players or NPCs to the fight. However, this time the players will have to face both the boss itself and the invaders at the same time and not only the invader. Another difference is that while the Mirror Knight is able to do this multiple times, the Old Monk can summon only one invader per fight.
 * While playing online, in the corridor before the Mirror Knight's arena, players will be able to see several candles. According to Yui Tanimura, whenever any player online is killed at the hands of the Mirror Knight, a new candle will be lit, and other players will see it in their own worlds.
 * Early promotional footage of the Mirror Knight shows a character resembling Oscar, Knight of Astora emerge from the mirror shield, likely a nod to Oscar's cut content from the first title.