The Armored Robotic Custodian is a large sentinel robot designed to fend off invaders within the Batcave: Inner Sanctum.
The sentinel is the first boss encountered in the Batcave: Inner Sanctum raid, and is widely regarded as one of the most difficult bosses even after being weakened in an update.
- Brother Eye and Brainiac have taken over the Batcave's mainframe and, along with it, the substantial automated defense and security forces. Both heroes and villains battle against Earth's real enemy in the Batcave: Inner Sanctum raid.
- In Gotham Under Siege, if Batman comes into contact with villains, he will deploy an ARC, which can knock players back by a far distance. Batman would disappear soon after.
- The A.R.C. is a boss fight in Metal Pt. I: Batcave Breach.
The A.R.C. will start out with only one ability - the Clean Sweep Protocol, which creates a huge torrent, knocking back players and objects alike. However, every time it loses about 20% health it will protect itself with a shield, becoming immune to all damage and taunts and will chase a random player while reinforcements arrive. After approximately 30 seconds it will consume one of the drones and gain a new ability based on the type of drone consumed:
- Wing Armor: Whirlwind Attack - creates a vortex that will suck in all nearby players and objects, dealing damage.
- Omega Sentry: Sonic Blast - powerful sonic attack severely damages all players within medium range of A.R.C.
- Security Drone: Rocket Barrage - large amounts of damage in close range.
- OMAC Prime: Doom Spin - a Whirlwind Attack almost identical to the one used by the Primes, but with an added tornado effect. Deals extreme melee damage and knocks back players.
- OMAC: Energy Blast - targeted at the tank. This does huge amounts of damage and needs to be dodged.
- Arrester Drone: Stun Beam - Unbreakable single target stun.
- Pacifier Drone: Riot Foam - a significantly more potent version that will always encase it's target after several seconds - lasts 5 seconds.
Due to the high amount of damage and AE knockbacks this boss does in close to medium range, it is highly recommended that everyone including the tanks stay as far away as possible, especially after 2 or more drones have been consumed. The raid can focus down different types of enemy drones to deny the A.R.C. access to their abilites, but once a drone has been destroyed, the other one will always be integrated.
The main threat is the Omac-derived Energy Blast which will fire many aimed projectiles that deals around 600~1000 damage. As a rule of thumb tanks should always fight it at range when possible to better avoid this.
It is easier to say which special attack isn't extremely deadly - Riot Foam and Stun Beam doesn't do much damage in comparison to Doom Spin or Sonic Blast. Omega Sentries and OMAC Primes should be destroyed as quickly as possible as these two attacks could easily wipe out a whole team in one go.
The feat related to ARC takes several runs, and is one of the hardest feats to complete yet it is only marked with two stars.
Essentially you have to have him absorb one of each of the above adds for the feat and then kill him. Since the spawns are random generated and they only spawn at two-thirds and one-third of healthbar, it can be a handful to complete this feat and it's definitely not worth the effort for the tiny reward.