Hello everyone and welcome to my 177th analysis, this time featuring Llum the Iron Leader.
Overview: Judging by the Base Powers and Bleeding effects of her Metal moves, and increased Base Strength, one can see that this form was intended to be an attacker. While you can somewhat manage this thanks to her damage boosting attacks and aforementioned moves, her Base Strength does fall short of traditional attackers, who are expected to have at least 3575 Strength. Instead, one should preferrably focus on the supportive qualities Iron Leader has, offering excellent status control through her moves and Bulwark allowing her to operate even under assault from debuffs. What's better is that Iron Leader can manage to be both an attacker and a supportive monster at the same time, something not many monsters can claim.

Builds:
Monsters that have access to Group 4 skills will have a slightly different build path. I will list the most viable builds for each Rank since some moves in Group 4 are pivotal to some sets' success. The monster's role will likely remain the same, however, so this won't be exhaustingly long as I won't repeat the same things.

Rank0:
(Support)
Moves:
-Sabotaged Rations
-Leader Shout
-Silver Bridge
-Comforting Words
Runes: 3 Speed/3 Team Speed
Mutant Rune options: Speed&Life, Team Speed&Team Life
Relics: Armors and Essences

Build Explanation:
Sabotaged Rations is primarily used for the AOE buff removal, but the Stamina Leak and Special Weakness definitely do help. Leader Shout is there to clean all debuffs from your team, and restoring their health in addition to giving the Damage Boost is highly appreciated as well. Silver Bridge is a single target Sabotaged Rations to have another buff removal after enemies try to get their buffs back, and is her best weapon against Dodge Area monsters like Wyrmlad. Lastly, Comforting Words is the best remaining supportive option.
A 3 Speed spread allows Llum to move as often as possible to use her status effect control moves for disruption, but 3 Team Speed is also useful to speed up your allies instead.

(Attacker)
Moves:
-Sabotaged Rations
-Leader Shout
-Abdicator
-Skin Heater/Silver Bridge
Runes: 2 Strength 1 Speed
Mutant Rune options: Strength&Life, Speed&Life

Build Explanation:
Iron Leader is the only Llum form with somewhat usable Base Strength, and her Bleeding effects can be useful to further chip opponents down. Sabotaged Rations is her best AOE at this point while Leader Shout doubles as both a damage boost and debuff removal. Abdicator is her most powerful single target attack. In the last slot, either Skin Heater for another AOE or Silver Bridge for another somewhat powerful single target attack that also removes buffs.
2 Strength 1 Speed with Life Mutations is the standard on attackers.

Rank1: Iron Leader learns "Battlefield Speech" at this level, a move that removes all debuffs from all allies and gives the Double Damage and Precision.
(Support)
Moves:
-Sabotaged Rations
-Battlefield Speech
-Silver Bridge
-Leader Shout
Runes and Mutant Runes are the same as given above.

Build Explanation:
Battlefield Speech is a very flexible move; it can be used to boost attackers, increase the chances of status effects landing, or simply to clean your teammates of debuffs. Leader Shout replaces Comforting Words on the last slot for the increased utility it provides over that move.

(Attacker)
Moves:
-Sabotaged Rations
-Battlefield Speech
-Abdicator
-Skin Heater/Silver Bridge
Runes and Mutant Runes are the same as given above.

Build Explanation:
Mostly the same moveset here, Battlefield Speech replaces Leader Shout.

Rank2: Iron Leader learns "Accepted Fate" at this level, a Base 50 unresisted AOE that remove all debuffs from all enemies, then applies Blind and Damage Reduction to them.
(Support)
Moves:
-Battlefield Speech
-Accepted Fate
-Sabotaged Rations/Leader Shout
-Silver Bridge/Leader Shout
Runes and Mutant Runes are the same as given above.

Build Explanation:
With Accepted Fate, Llum gets a staggering total of 3 possible buff removal moves. Not only this, but the Blind this move inflicts acts as a soft deny which will make enemy monsters very likely to miss their status effects, especially with Llum's Bulwark. For this reason, 3 Speed becomes more noticeable at this level, though 3 Team Speed is still very good to have.

(Attacker)
Moves:
-Battlefield Speech
-Accepted Fate
-Abdicator
-Sabotaged Rations/Silver Bridge
Runes and Mutant Runes are the same as given above.

Build Explanation:
Accepted Fate's awesome 50 Base Power, along with incredible utility, makes it a great weapon for the Attacker set. Combined with Battlefield Speech's Double Damage boost and debuff cleaning, she can set up for a big AOE while ridding her team of annoying debuffs.

Rank3: Iron Leader learns "Veinboiler" at this level, a Base 50 AOE Metal move that applies Bleeding to all enemies.
Support Llum doesn't need this, as it's purely offensive.

(Attacker)
Moves:
-Battlefield Speech
-Accepted Fate
-Abdicator
-Veinboiler
Runes and Mutant Runes are the same as given above.

Build Explanation:
With Veinboiler, Iron Leader has 2 Base 50 moves under her belt, something not many other attackers can claim. Its power cements its place in the last slot.

Teammate Options: Not having an attacker with Support would be a terrible waste, preferably one with a strong AOE to wipe the enemy out with the boost given by Battlefield Speech. For Attacker, not many interactions exist. For more Teammate options, check out this article.

Countering Llum the Iron Leader: Clearing your team of debuffs will at least rid them of Blind. Try to deny Llum with things like Stamina Drain or CD Activation to prevent her from moving at all if possible. Clear Attacker's Double Damage buff, and you'll take away most of her destructiveness, but she still does have status effect control so beware that. For more Counter options, check out this article.