Octopath Traveler COTC [SEA] Warrior Training EX5 (5F EX1) (First Clear)

This tower's gimmick is about using E.Atk to break the sentinel before breaking the boss is allowed. And sentinel weakness always remained hidden.
Every 3 turns, the boss will unleash a 1-hit NUKE move at end of turn. Furthermore, unlike other towers, this one has 15 turns time limit.
Finally, the boss will act 2 times per turn.

The Sentinel have 4 patterns of weakness.
ice, dark
ice, light
light, dark
lightning, wind
The boss has four patterns of weakness as well. But sword and wind are all we need to know.

The play is quite straightforward. Taking two turns to break the sentinel and the boss the following turn (Before the boss unleashing their 1hit Nuke move.) then Nuke then breaking sentinel again.

However, surviving the boss attack is the most difficult part. The combination of the 3-hits random target and AoE attack is catastrophic.

Tip to break sentinel is "We spam four differences E.atk in the first turn and keep in mind its weakness. Next turn uses only the weak E.atk. the rest of member simply healing, buffing, debuffing, or shaving the boss shield"

The majority of the boss attacks deal Physical damage. so equipped for the P.def focus equipment. And ensure to equip HP Regen accessory.

For character we need a lot of Nuker. (4 unit is the best)
Every 5-star unit aside from Eliza can be a nuker.

Sentinel shield shaver requires a large variety of elements.
Eliza is the best with 3-hits light ST and she also the best healer.
Tikilen can perform her job very well with 2-hit AoE wind.
Sigrid has 2-hits lightning ST.
Lionel has 3-hits ice ST and 3-hits sword ST that can inflict 10% P.def down.
2B has 2-hits dark AoE and 15% P.def down debuff.

Trish can be a budget ST healer.

In my opinion to clear EX5 floor. We require at least two units from the "Eliza, Lionel, or 2B".

Example for Sentinel shield shaving combo

ice, dark
Lionel 3-hits ice + 2B 2-hits dark = 5
2B 2-hits dark + Fiore 1-hit dark = 3

ice, light
Lionel 3-hits ice + Eliza 3-hits light = 6
Eliza 3-hits light + Miles 1-hit light = 4

light, dark
2B 2-hits dark + Eliza 3-hits light = 5
2B 2-hits dark + Miles 1-hit light = 3
Eliza 3-hits light + Fiore 1-hit dark = 4

lightning, wind
Tikilen 2-hits wind + Sigrid 2-hits lightning = 4