Battle Nations Wiki
Ancient Sentinel
Rank/Title Security Robot
Affiliation Ancient Civilization
Weapon Laser
Chemical Gas
Crushing Arm
Incinerating Arm
Spawnrate 3 - 8 days
(Levels 50 and above)
Mission requirements An Ancient Doom
Battle Icon LandEncounter ancientSentinel icon EncounterIcon AncientSentinel icon


The Ancient Sentinel is a reoccurring mega-boss encounter introduced in the 2.85 Patch for players who have defeated the Ancient Construct and are level 50 or above. It appears in the Ancient Ruins, after a brief dialogue between the characters.

The Ancient Sentinel is comprised of three different parts:

Each part has its own pool of health and armor, as well as unique set of attacks. Each part has an incredible amount of damage reduction against all damage types, and coupled with a devastating array of indirect line-of-fire attacks that can target multiple spaces of the battlefield; the Ancient Sentinel is truly a challenge, even for the most experienced armies.

The Ancient Sentinel has Stat-Armor-HP 2450 and both the Ranged Arm (the laser arm on its right) and the Melee Arm (rake arm on its left) have Stat-Armor-HP 1400. Altogether, the Ancient Sentinel has combined total of Stat-Armor-HP 5250. That is more than twice as much health as the Ancient Construct.

The Ancient Sentinel can be beaten by destroying only the Main Body but this will yield less Resource-SP SP and Gold Gold.

The spawnrate of the Ancient Sentinel is 3 to 8 days.

Like the Ancient Construct, the Ancient Sentinel will disappear if not killed within 72 hours.


All three parts of the Ancient Sentinel have an unbelievable amount of damage reduction, so that a Rank 5 Tank Killer will only do about 150 damage, assuming all shots hit. The Melee Weapon System can be stunned while the Ranged Weapon System can be frozen.

Fielding Soldiers could be a disadvantage since the Main Body and the Ranged Arm have attacks that have high armor piercing AND critical bonuses against infantry. The Melee arm has critical bonuses against Vehicles, and is ineffective against infantry. Tanks tend to have more health and armor as well as better damage reduction to survive the Sentinel's onslaught. One working strategy is to use 2 Rank 6 Veterans, 2 Rank 6 Raider Recruits, or 2 Eagle Eyes (Equal defense and dodge but way less health) in the front line. The high dodge and defense of these units allow it to survive the attacks of the Sentinel as long as the Ranged Arm is out of action. This strategy also helps when there are no vehicles in the front row. It makes the melee arm unable to use the checker attack, making it nearly useless.

In recent updates, however, new obtainable units such as the Legendary Sandworm makes defeating this recurring mega-boss an easy chore- even as low as level 50. A common strategy includes the placement of three legendary sandworms, a nomad or elemental trooper, and any other units that could inflict heavy damage to the sentinel. These units may include Wild Boar I, Legendary Boar, Legendary Raptor, and the Wild Boar II.

The Ranged arm can be frozen, which takes it out of action for a few turns as well as making it more susceptible to every damage type. Note that StatusEffect-frozen Freeze replaces its damage reduction with 125% susceptibility. Fielding a unit capable of StatusEffect-frozen Freeze paired with a high-rank Tank Killer can dispatch the Ranged Weapon System quickly. However, Tank Killers are not recommended for fighting the Ancient Sentinel as they die quickly. Also, it can be affected by the Suppressor flammable icon Explosive status effect, which replaces its damage resistance with a damage increase of 400%. Unfortunately, the only unit that causes this status effect is the Weapon Technician. After putting the Suppressor flammable icon Explosive status effect upon it, it can easily be taken out by a R4 Tank Killer.

The Melee arm can be stunned, and given that it has the lowest cooldowns on its attacks, stunning this arm can buy the player a turn to do some damage to the Sentinel or heal a critical unit. Also, the Melee Arm's most devastating attack can only hit vehicles on the front line. If there is only infantry on the front line then the attack is negated.

The main portion of the Sentinel is immune to all current status effects, and has even more damage resistance against attacks than the Ranged arm or Melee arm. However, it has little resistance to the Legendary Boar's Chilling Roar attack, so fielding Legendary Boars would be a good idea, especially since they have a decent amount of health and armor.

Battle Map & Rewards[]

Number of units allowed: 10
Allowed unit types: Default
Environmental DoT: None
Ignorable: Melee Weapon System
Ranged Weapon System

Hero ancient robot 2 arm right front
Ancient Sentinel
Hero ancient robot 2 arm left front

Reward Chance
Gold 10,000-25,000 Gold 100%
Gears 20-35 Gears 100%
Bars 25-30 Bars 100%
Resource-widget 2-5 Widgets 100%
Resource-laurels 2-5 Laurels 100%
Resource-chem 10-25 Chemical Vials 75%
Veh ancient fragmentClaw icon Melee Fragment 2%
Veh ancient fragmentBlaster icon Ranged Fragment 2%




Main Body

Weapon Animation
Idle Hero ancient robot 2 body front idle
Laser Hero ancient robot 2 body front attack1
Chemical Gas Hero ancient robot 2 body front attack2

Melee Weapon System

Weapon Animation
Idle Hero ancient robot 2 arm left front idle
Incinerating Arm (Pulverize) Hero ancient robot 2 arm left front attack1
Incinerating Arm (Vehicle Crash) Hero ancient robot 2 arm left front attack2

Ranged Weapon System

Weapon Animation
Idle Hero ancient robot 2 arm right front idle
Crushing Arm (Scorching Ray) Hero ancient robot 2 arm right front attack1
Crushing Arm (Diffusion Ray) Hero ancient robot 2 arm right front attack2