Skill/Spell:
1. Inferno Magic :
- Immolate + Wildfire
Small AOE range, low cost mana, 8 sec dot, cooldown 10s, a lot better than Flash Fire
- Flashpoint
An awesome passive, everytime you land critical hit including normal attack, your next spell have no cooldown, cd 10s.
- Clean Burn
Another awesome passive, everytime you cast a spell your cooldown times reduced by 1%, spirit blade is spell so spam it!
- Pyromancer
- Chaotic focus
THIS IS the key for nuking the enemy, whenever you cast a fire spell, the spell consume 50% of your current BARRIER, the larger your barrier, the greater your damage bonus.
- Fire Mine + Searing Glyph
Your main damaging skill, 1600% weapon damage + dot 8 sec for total 1600% dmg.
2. Storm Magic :
- Energy Barrage,
- Conductive Current
More awesome passive, the more you spend mana, the more powerful your spell.
- There is some good skill on Storm magic, but for now Conductive Current is enough
3. Spirit Magic :
- Barrier
Hell yeah
- Guardian Spirit
This one is helpful passive, once your Health under 25%, a Barrier is automatically cast on you, you can escape death from this passive skill as long the skill isn't on cooldown.
- Mind Blast + Fortifying Blast (take this upgare later if you had more skill points to spend)
- Strength of Spirits
This is a must passive to get, this makes your barrier stronger which mean this passive makes your spell stronger thanks to Chaotic Focus.
4. Winter Magic
- Fade Step
Teleport? why not 
- Winter's Grasp (take this later if you have more points)
- There is some usefull spell/passive on this tree, skip for now.
5. Knight Enchanter
- Spirit Blade
No cooldown with low mana cost, its good for breaking enemies barrier, you can use this skill to reduce cooldown from Clean Burn.
- Fade Cloak + Decloaking Blast
Invulnerable from any attack for 2s, explode for 1000% weapon dmg,
- Combat Clarity
Mana regen rate +50%, sweeeeet
- Fade Shield
This one is a must have passive, it generate 30% barrier from all your attack. Damage from Fire Mine = instant fill your Barrier
- Knight Protector
A helpful one, barrier decay reduction 30%
Total 19 Skill points, i got two pts from Amulet of power, one from inquisition perk, one from human racial bonus.
Gear:
At earlier its hard to land critical hit so we can't see Flashpoint full potential, i got my critical chance gear after finishing main story at Winter Palace, i got a hat that increase Critical Chance by 5% and Cunning by 5 pts, i got tier 3 staff grip (Wrapped Staff Grip) too, it can be crafted using offense : 6 leather, util 3 cloth, which mean you can put critical chance effect on it for total 11% crit chance, the other one is critical chance ring, you can put two rings if you want. My other ring is Enhanced Barrier ring which increase barrier duration, its helpful. My critical chance atm is 25%, aim for 30-40% then pump your crit damage. Gear main stat is Willpower, its increase your damage and magic defense, while Magic stat increase your damage and barrier damage, you didnt need barrier damage because Knight Enchanter already have Spirit Blade which is pretty good at breaking enemies barrier.
Party :
- Cassandra - Templar
She's good, some of her skill can increase your damage and resistance.
- Solas - Rift Mage
He's really helpfull, take Rejuvenating Barrier from Spirit Magic, its regen mana by 35% whenever you or allies have an active barrier. If you want more damage and easy nuking Fire Mine, put him in party, his Pull of the Abyss spell can pull nearby enemies in one place, then use his Veilstrike or Stone fist to weaken them for extra damage, then put your Fire Mine in the center, you can use Fade Cloak and go near them for another huge damage.
- Fourth member, just add whoever you want.