Anthea and Concordia

Anthea and Concordia are members of Team Plasma and after with they and the others who are loyal to N are on the side of good while the members loyal to Ghetsis are on the side of evil.

Black and White
Anthea and Concordia are first seen in the opening sequence of Black and White. The player only encounters them in N's Castle, where Anthea heals the player's Pokémon, while Concordia tells the player more about N's past and Ghetsis.

Black 2 and White 2
Anthea and Concordia are seen in the original Team Plasma's safehouse in Driftveil City. They give the player more backstory about themselves and N, revealing that all three of them were orphans that Ghetsis took in. They were then put in charge of caring for N while he was a child.

Anime
Anthea and Concordia debuted at the end of Team Plasma's Pokémon Manipulation!, where they rescued N after he was injured fighting Colress and Team Plasma in a city. With Ash and his friends in tow, they took N to their secret refuge in another dimension where they protect injured Pokémon.

Anthea and Concordia also appeared in the next episode, where they and N told Ash and company about their past with Team Plasma and Ghetsis. With N, they explained that the three of them were raised in a great mansion by Ghetsis and Team Plasma. However, when Reshiram destroyed the mansion during a ceremony two years prior, they realized Ghetsis was lying to them and helped N escape. Because of these experiences and Ghetsis's training, Anthea and Concordia were deeply distrustful of humans and even initially believed that Ash and his friends led Team Plasma to their hideaway. Ash, Iris and Cilan defeated the Team Plasma members, who had found their way into the dimension using a special machine, causing Anthea and Concordia to have second thoughts about them. After this, N joined his foster sisters, and disappeared into the mist. When the mist faded, N, Anthea, and Concordia were gone, and Ash and his friends found themselves on a wide field, where they saw the Dragonspiral Tower, towering a little distance away.

They were briefly seen at the beginning of Meowth, Colress and Team Rivalry! and in N's fantasy in Ash and N: A Clash of Ideals!.

Anthea and Concordia made another appearance in What Lies Beyond Truth and Ideals!, where they came to the White Ruins to aid N in the fight against Ghetsis and Team Plasma. However, despite providing a distraction for N to free himself, Colress used his machine to control their Pokémon, luckily they were freed among the other controlled Pokémon when Reshiram destroyed the machine. At the end of this, Anthea and Concordia were finally able to realize the reality that not all people were cruel to Pokémon, finally enabling them to move on from their past. They are N's allies and have similar abilities for hearing the voices of Pokémon.