| 1,500 |
|"This ultra-giant size missile tank was created in cooperation with Mars People. Gen. Morden himself is aboard."|
As Mars Currency can only be obtained by trading in platinum evolved units, it is unlikely for low level players (and free players) to obtain the Iron Sentinel. While the Iron Sentinel has unique items (as with most boss-type units), most of these items can also be bought from the shop.
The Sentinel itself is a very large multi-treaded tank that shoots missiles and projectiles from its ball turret. If 4 is unlocked, upon reaching 0 health, it will convert into a second form that shoots even larger missiles with a wide area of effect and dealing much more damage.
The Sentinel is rarely used, since it typically struggles against lower AP cost units like Yoshino, who can defeat it with ease in a one-on-one fight.
Missile (Spread) Launches a salvo of missiles from its side. If in second form, shoots out very large missiles.
Big Missile (Spread) Fires larger missiles from its main turret, and bombs from its side.
|50||70000||77000||84700||93170||102487||* HP might be increased by skills / items or buffs|
The Iron Sentinel uses a selection of unique items unavailable to any other units. Like the parts for the Sentinel itself, these can only be obtained via the Mars Shop (or fused using other items from the same).
| Strengthen Weapons|
Strengthen all attack power by (20%, +1% each level).
| All-Around Armor|
HP will increase by (20%, +1% each level).
| Equip Anti-Armor|
Critical rate for all attacks will become (10%, +0.5% each level).
| FORM CHANGE|
Even if beaten once, gets back to life and turns in 2nd form via HP (20%, +1.6% each level).
In order to obtain parts for the Iron Sentinel, surplus parts from platinum-framed units must be traded in at the Mars Shop:
- 1x Unit Parts (Normal) grants 1.
- 1x Unit Parts (Rare) grants 10.
- 1x Unit Parts (Super Rare) grants 40.
1,000 points are required per Sentinel part. Hence:
- 1,000x Unit Parts (Normal) grants one Sentinel part.
- 100x Unit Parts (Rare) grants one Sentinel part.
- 25x Unit Parts (Super Rare) grants one Sentinel part.
Building on that:
- 80,000x (Normal parts), 8,000x (Rare parts), or 2,000x (Super Rare parts) grants a silver Sentinel.
- 180,000x (Normal parts), 18,000x (Rare parts), or 4,500x (Super Rare parts) grants a gold Sentinel.
- 330,000x (Normal parts), 33,000x (Rare parts), or 8,250x (Super Rare parts) grants a platinum Sentinel.
Furthermore, various items for the Sentinel must also be purchased using Mars Points:
- 900x (Normal parts), 90x (Rare parts), or 23x (Super Rare parts) grants the first skill.
- 6,500x (Normal parts), 650x (Rare parts), or 163x (Super Rare parts) grants the second skill.
- 71,500x (Normal parts), 7,150x (Rare parts), or 1,788x (Super Rare parts) grants the third skill.
- 221,500x (Normal parts), 22,150x (Rare parts), or 5538x (Super Rare parts) grants the fourth skill.
- 1,121,500x (Normal parts), 112,150x (Rare parts), or 28,038x (Super Rare parts) fills the fifth panel set.
1,451,500 Mars Points are required to fully evolve and equip an Iron Sentinel (or 36,288 Super Rare unit parts). On the other hand, a silver Sentinel with only the first four skill panels unlocked costs a relatively low 80,000 + 221,500 = 301,500 Points (7,538 SR parts).
One can easily gain massive amounts of the items by hoarding up Battle/Guild Medals and Gold Bars from Battles, Guilds and P.O.W. Rescue. From the respective shops, buy only Super Rare unit parts (e.g Stone Turtle, Leona, etc.), as they provide the best ratio for Iron Sentinel parts compared to Rare and Normal rarity units. It is even better to purchase the Super Rare unit parts during a discount event, where the items are sold at 30% off their original price (so the parts would cost 350 of their respective currency). Since waiting for the stores to restock manually can be time consuming and unnecessary, it is best to continually refresh the stores' stocks and purchase Super Rare unit parts. This will cost much more currency though.
- The Iron Sentinel is instead referred to as the "Iron Slider" within Metal Slug Attack's code. Its sprite sheet portrays the original Slider from Metal Slug 6, angled downhill - the game rotates its images to a levelled orientation at run-time.