This is chapter 3-P of my FE10 HM 0% growths playthrough, commentated by Mekkah and me. It is completed in 6 turns.
This chapter gets a bit of an unfair rap for being extremely RNG-dependent, because of how little the player can do to influence Skrimir. In actuality, there are ways to ensure that Skrimir almost always finishes 3-P in 6 turns (this is what happens when you play this chapter a way too much...). Once I figured out the 3 conditions on turn 4 that I talk about in the commentary, I was always able to 6-turn the chapter as long as I met them.
5 turns is possible with heavy RNG manipulation, with a slightly different approach to this chapter. Skrimir's turn 1 action is always counterproductive, but no matter where he ends up, he's within 36 squares from the arrive tile, so arriving in 4 more turns is theoretically possible. First, you want to target halberdiers and crit them with the Killer Ballista, which allows them to be finished off by a single laguz attack. This prevents a traffic jam at the first enemy barricade. Second, the Greil Mercenaries need to advance even faster than in the 6-turn strategy, which necessitates some of their combats to be converted to shoves or rescue drops. So their remaining combats must be converted to ORKOs, typically by rigging low % crits using weapons such as the Killer Axe, Killer Bow, Ike's Ettard, and Soren's Thunder. Transfers would help immensely with this, too. Third, the laguz generally need some favorable RNG to break past the enemy general barricade (from Toffee's experimentation, often this entails a laguz dying to a general on enemy phase so that Skrimir will take their place on turn 3 NPC phase). But this often depends on what the laguz do on turns 1 and 2.
Itemfinding in 3-P: Coin (48%)