| 900 |
|"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's generally easiest to obtain it by gathering Rare unit parts from the MSP crank. Once all the crank units have been fully evolved, every additional ~2.43 million MSP spent on 10x pulls will average enough Mars Points for a Sentinel part - and so a platinum Sentinel (or Rootmars Slug) can be obtained for about 800 million MSP (minus however many additional points are earned from events and other cranks).
The Sentinel itself is a very large multi-treaded tank that shoots missiles and projectiles from its ball turret. If 4 is unlocked, when first destroyed, it will switch to a secondary form that shoots even larger missiles with a wide area of effect and a higher damage output.
It has fairly high health for a backline unit, and its large size and long range missiles makes it a formidable foe to fight, especially when buffed. The 2.13.0 update doubled its base health and long range damage, increased its special damage by 20% per shot, and additionally had its special fire extra shots.
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||140000||154000||169400||186340||204974||* 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 by themselves is unnecessary, it is best to continually refresh the stores' stocks and purchase Super Rare unit parts.
- 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.
- The Iron Sentinel was buffed as of the 2.13.0 update, following player complaints about how weak it was for the time it took to use it properly.