Just started on Hikari what duel skills should i be trying to get?

[HollowKing]

Should I be trying to get a variety of things to break foes like elemental attacks and other weapon attacks? Do attack skills with other weapons he doesn't have scale with his attack power or is it like he is attacking without a weapon? Should I be trying to get weapon skills for the weapons he already has?

[Watcher Rat]

I would keep your eyes open for:

Twin Serpents, which is a fantastic AOE spear skill that hits all enemies twice and is great for breaking. This can be found early on in the Beastling village, and also later on in Hikari's 5th chapter

Merciless Blade, primarily because it cannot miss, and is excellent for farming Cait and Octopuff enemies. This can be found in Tropu'hopu.

Resting, Resting is like the Merchant's Rest ability, it recovers HP and SP and can be obtained fairly early on in the Beastling village.

Limb From Limb hits four times, and can easily break the damage limit later on, it's easily one of the strongest abilities Hikari can learn. It is learned in Stormhail, so this will be a fairly late acquisition.

Divine Dual Edge is an AOE sword attack that hits all enemies twice; this and Twin Serpents are phenomenal farming skills - it is obtained from the boss of Hikari's third chapter.

Deep Analysis is similar to Analyze, but it reveals three weaknesses at once without charging up. You can get it in Flamechurch.

Defiant Stance comes from Oresrush, and buffs attack and defense nicely.

Last Gasp does more damage the lower your health is, and can save you in an emergency, it can be found in Montwise.

Mythical Bore is a last resort type move; it consumes all of your SP to execute a massive attack, and can easily hit for 99,999 damage with limit break. It's found in the Nameless Village.

Divine Protection costs 100sp and makes you immune to any hit; it can be boosted to protect you for 4 times, making it broken in a lot of fights. It's found in Canalbrine.

Shield Thief works similar to Tenemos' Latent, and reduces enemy shield regardless of weakness. It's found in Winterbloom

Frenzied Fire does AOE bow damage 4-8 times, but can miss (it will rarely hit 8 times without insane accuracy). Good breaking ability though. It's found in Timberain.

Fatal Fang is similar to the above, but with dagger hits instead of bow. It's found in Clockbank.

Aggressive Thrust is similar to the previous two, but with a spear. It's found in Canalbrine.

Compound Formulae hits fire, light, and dark weaknesses all at once on all enemies, but is only really useful if you build Hikari as a magic user (although it can get some quick breaks here and there). It's found in Montwise.

Deep Sleep is great for healing; it recovers 50% of your HP and SP, but puts you to sleep for 4 turns. However, equipping a Wakeful Stone accessory negates the negative, if you're ok with sacrificing a slot to that. The ability is found in the Nameless Village.

Those are the best ones I've found to date. I personally would not get rid of Divine Dual Edge since, as far as I can tell, only a single enemy in the game can give you that skill. Twin Serpents, as I mentioned, is great too since the two combined abilities are great for quickly clearing enemies (and with the Apothecary HP/SP restore passive, you can easily farm nonstop with these alone). The others are up to you; the healing ones are better for when you're doing Duels or if you're on a solo run. Merciless is great for rares, but not amazing otherwise.

[HollowKing]

Wow I was not expecting such a thorough and thought out answer, this was way more than I was expecting!

A lot of these abilities sound super cool i am heading to places where I can access the early ones you recommend now and I will refer back to this later in the game for the later acquisitions.

I am loving this game and being able to acquire these cool abilities by dueling different characters is very cool design once again thanks for advice!