A guide on how to take on the fourth Totem Pokémon in the game: Totem Lurantis!
Totem Lurantis is a level 24 Grass-type Pokémon, with access to the following moves:
Razor Leaf is a Grass-type move that deals damage and has a high critical hit ratio.
X-Scissor is a Bug-type move that simply deals damage.
Solar Blade is a Grass-type move that deals a lot of damage but has a charging turn (unless used under harsh sunlight or skipped with a Power Herb).
Synthesis is a move that restores HP, which is more effective under harsh sunlight.
At the start of the battle, Totem Lurantis' aura gives it a boost of +1 Speed. Furthermore, is has the Ability Leaf Guard, which prevents the Pokémon from being inflicted by status conditions under harsh sunlight. Finally, it is holding a Power Herb, which enables it to use Solar Blade without a charging turn once.
Totem Lurantis can call two allies. The first of them is a level 22 Trumbeak, a Normal/Flying-type Pokémon with the following moves:
Rock Blast is a Rock-type move that hits 2-5 times. Pluck is a Flying-type move that also steals any Berries from the target and consumes them. Supersonic may confuse the target, and Screech reduces the target’s Defense by two stages.
Trumbeak's Ability Keen Eye prevents it from getting its accuracy lowered.
The second ally that can be called is a level 22 Castform, a Normal-type Pokémon with access to the following moves:
Sunny Day sets up harsh sunlight for 5 turns. Water Gun is a Water-type move that deals damage. Headbutt is a Normal-type attack that deals damage and may cause the target to flinch if they move after Castform. Weather Ball deals damage of which the type depends on the weather; under no specific weather condition it is Normal-type, under harsh sunlight (which it can create with Sunny Day) it is Fire-type.
Fire-types are very useful, as they resist Grass-type attacks and hit back for super-effective damage. This is made even better thanks to Firium Z giving access to the Z-Move Inferno Overdrive, and the harsh sunlight that may be set up and increases their damage done by 50%. They only need to be a little careful of the occasional Rock Blast by Trumbeak (or Castform’s Water Gun which shouldn’t hit hard, especially under sunlight).
Poison is also a nice type, and so is Flying (be careful of Rock Blast too). Bug is more risky because of Rock Blast, Pluck and Fire-type Weather Ball.
Salandit is the single best option for this battle; with its Fire/Poison typing it resists Grass-type moves twice. If sufficiently leveled, a Salandit’s Inferno Overdrive should be able to OHKO Totem Lurantis (especially if there’s harsh sunlight up). Female Salandit (who may evolve into Salazzle eventually) are useful later in the game too.
Fletchinder is also useful for its 4x resistance to Grass (just watch out even more for Rock Blast).
This battle can turn out very differently depending on which ally is summoned first, and which strategies you are willing to follow as well. If it is Trumbeak, you may want to focus on Totem Lurantis (as is usual for Totem Pokémon battles) and avoid Castform’s Sunny Day altogether. If Castform shows up, you may try to avoid it setting Sunny Day with Cloud Nine or setting up rain (with Rain Dance or the Ability Drizzle), or just try to KO Castform. Alternatively you may let the harsh sunlight be and use it to your advantage if you use Fire-type Pokémon.
Just note that if harsh sunlight is up, you have to watch out for one-turn Solar Blades, very powerful Synthesis and STAB Fire-type Weather Balls; although OHKO with Inferno Overdrive becomes easier.
In practice what matters a lot is that you knock out Totem Lurantis quickly (since its defenses make it possible enough), or else it may keep healing with Synthesis. It also has very high Speed, so don’t worry about outspeeding it, better use a Pokémon that can withstand a few attacks and hit back hard as well. Even if harsh sunlight never shows up, you may expect a single one-turn Solar Blade because of Power Herb.
Note that Trumbeak can be a troublesome ally with Screech, making things easier for Totem Lurantis to knock you out, and Supersonic causing the annoying confusion.