I think Darmanitan is more useful than Chandelure because it evolves earlier, isn't weak to dark, has a better ability, and learns belly drum and several useful coverage moves. Darmanitan performs better against Grimsley, N, and Ghetsis, as well as several of the bosses that you need to fight before Celestial Tower. This is the moveset I'd recommend.
Darmanitan
EVs: 100 Spe
- fire punch/flare blitz
- work up/belly drum
- dig
- superpower
Availability: Early-game (40% chance to appear in Route 4).
Typing: Save for Drayden/Iris, Fire hits all Gym Leaders and Elite Four members for at least neutral damage and is hit super effectively only by Clay.
Stats: Darumaka is decently fast, and its high Attack buffed up by Hustle allows it to hit every foe hard; its shaky bulk is fixed by Eviolite. As a Darmanitan, it hits even harder, is way faster, and has enough bulk to take neutral hits well and even avoid OHKOs from super effective moves.
Movepool: It learns Fire Punch at level 22, Belly Drum (which it can safely set up with as a Darmanitan) at level 30, and Flare Blitz at level 33. Hammer Arm comes upon evolution, and Superpower is learned at level 47. TM-wise, it can be taught Brick Break as an alternative to Superpower, Rock Slide, and Dig, the latter of which is good for Shauntal and Ghetsis's Fire-resistant Pokémon.
Major Battles: As a Darumaka, it only ever struggles against Clay. Burgh and Elesa lose to Darumaka, although it needs Eviolite for both. As a Darmanitan, it sweeps all the other Gym Leaders, with Drayden/Iris falling to Belly Drum. At the Elite Four, it can use Belly Drum strategies again to sweep all but Marshal. It is useful against N and Ghetsis, the latter being swept if you use Substitute and X Speed in conjuction with Belly Drum.
Additional Comments: Although Hustle might be annoying, most of the misses are not fatal; it does not prevent Darumaka from being one of the best choices for an efficient run of the games.
Litwick
Availability: Late-game (100% chance of encounter at Celestial Tower's 2nd floor).
Typing: Fire/Ghost hits Bug- and Grass-types hard as well as major battles with Ice-types (Brycen), Psychic-types (Caitlin), and other Ghost-types (Shauntal). However, Grimsley's Dark-types as well as Water-, Rock-, and Ground-type coverage threaten it significantly.
Stats: As a Litwick, its stats are unimpressive, especially Speed, only getting somewhat acceptable with Lampent. However, as a Chandelure, it possesses really high base 145 Special Attack, good base 80 Speed, and acceptable base 90 Defense and Special Defense.
Movepool: Litwick relies on Flame Burst and Hex + Will-O-Wisp as STAB moves. It can be taught Fire Blast and Shadow Ball through TMs.
Major Battles: It does well against Brycen as Lampent or Chandelure, and can do well against Drayden. It also performs well against Shauntal and Caitlin and can contribute nicely to every other matchup, either by KOing a specific threat or by spreading burns.
Additional Comments: A Dusk Stone can be found in Mistralton Cave, allowing you to use a Chandelure against Brycen and more Route trainers, but requires a detour. Another one can be found on Route 10, but it comes later. Litwick's late evolution (level 41) is an offset for Chandelure's destructive nature. Flame Body is the preferred ability, as it burns contact move users 30% of the time.
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