This guide is made specific for getting the Flawless Conqueror title in veteran Maelstrom arena as a stamina Dragonknight.
Stamina Dragonknights are real men and don't chicken out with mega heals or shields. You will need above 20k health, so adjust that with either health trait on jewelry or in attributes.

Pros and cons:

+ good single target dmg and tanky at the same time, making ignore tactics easy.
+ decent stamina sustain with low cost abilities
+ High utility and speed
- Poor aoe dmg
- Low burst dmg
- Melee

Race:

Every stamina race can do it. I have done it with orc and khajiit. I have tried with a dunmer, but that was slightly weaker. A friend of mine did it with his argonian DK with this setup. I recommend any race with either stamina bonus or health bonus. I failed 8 times in a row with 19k health and 7 medium. Then after I switched to 1 heavy armor and 21k health, I did it 2 times in a row, went from 1-4 death each run, to 0.

Gear:

6 medium and 1 heavy OR 7 medium. Medium armor passives are much stronger than undaunted, so 5 medium 1 heavy and 1 light are not an option. Be sure to have the heavy armor passives as well. You will get some more health, healing recieved and resources back when hit as well as ressistance. I recommend heavy chest piece, even reinforced trait if you want to.

3 piece Agility or 3 piece Endurance with wpn dmg glyph: because of the stats they give.

5 piece of a stamina set, critical stats recommended. Examples:

Hundings rage: high weapon dmg and better heal with vigor.

Night mother: Better dmg then hundings, reducing enemy armor on crits.

Twice born star: Meta gear, can easily be used on other chars as well, good investment.

2 piece valkyn skoria: This set procs on every one of your dmg skills. It's free dmg and will be up constantly. DK lack burst. Skoria gives you burst dmg with is actually noticable in arena.

Back bar: Maelstrom bow precice: Eventhough you switch bar, your back bar stats still counts on some skills, like poison injection.

Main bar: Dual wield, prefer both maelstrom 1h with flurry bonus and highest crit chance possible, but whatever is available will work. DW have the highest stats in the game, both weapon dmg and weapon crit, witch also scales with ultimates, class skills and vigor heal.

Mundus stone:

If you have Agility jewelry, you need stamina regen mundus. If you have endurance jewelry, you can go dmg mundus. Use shadow before thief, because you have so many dots up, that you will always crit anyway, making the shadow mundus with crit dmg viable. Stamina recovery prefered at around 1200.

Skills and rotation:

Back bar:

Arrow barrage: Prefered before scortched earth because physical dmg and higher radius. We need that radius since we lack some aoe in this build. Also physical dmg scales with the armor reduction and our champion points. Keep this up at all time, even on single target.

Volatile Armor: This can proc skoria from the dot it gives. The other morph called Hardened armor, gives you a 1k ish dmg shield for 2 seconds and is completely useless anyway. While this skill is active, you will have Burning hearth passive active too, which gives you 12% healing recieved. Thats needed for the poor base heal from vigor.

Rearming trap OR burning breath: Whatever you feel like using here. I use burning breath to reduce armor on bigger mobs and bosses, although this is not nescesary with corrosive armor ultimate active.

Posion injection: Does actually descent burst dmg combined with a medium attack, making it possible to oneshot small mobs from range, for example the plants that slows you down at stage 3. Also a strong dot when target are below 50% health, and gets the flurry buff from maelstrom weapons.

Igneous weapons: Gives you alot bang for the buck. Both minor and major brutality when you activate it, and it gives ultimate and stamina back if activated while in combat. Even if major brutality lasts for 40 seconds, you still want to reapply this more often, since you get more from this skill. The minor brutality only lasts for 20 seconds. I recommend to use this together with volatile armor ever 20-25 seconds. This will make you able to keep both buffs up constantly. If you spam one of those skills too early and too much, you wont have magicka when you need it.

Ultimate - Corrosive armor: Ignores physical ressistanse, has a small aoe dmg every second and makes you take less dmg while active. This is good when you burn down bosses and ignore tactics. I can give one example of how to use this:
Stage 6 spider boss. You start the fight by putting all your dots on boss, then take the bug you need to kill on the totems. Then you stun the boss, and can reapply your dots and do dmg. Then right before the stun duration ends, you put up all your dot rotation again. Then the boss will spawn adds and now its time to press corrosive armor, ignoring everything around you. You have time to reapply another round of dots and boss should be dead by now, making it able to ignore all tactics and do one of the longest and caotic bosses in less then 1 minuite.

Main bar:

Rapid strikes: Single target spam, procs skoria and scales well with our champion point setup.

Unstable flame: High dmg single target dot, gets buffed from maelstrom weapons and has a low cost. This does not scale with armor reduction and champion points, so only use this in long fights.

Evil hunter: This build doesn't have enough magicka to activate flames of oblivion, so I use evil hunter. Some stages in arena have undead and then it is good to activate it. Gives you critical chance passive as well.

Twin slashes, blood craze morph: Decent dmg single target dot, gets buffed from maelstrom weapons and has a low cost. This scales with armor reduction and CP. This skill works every time since bosses and undead are no longer immune to bleed like they used to be. This also gives you some healing while bleed is active. Use this skill as often as possible, first dot to put on after a rapid strike.

Vigor: Its nice to have this heal on your main bar. Vigor is a short duration heal over time, and sometimes this needs to be casted every 4 seconds. You can't afford to weapon swap. Also this heal will be at it's strongest on the DW bar.

Ultimate - Flawless dawnbreaker: Gives passive weapon dmg while slotted.

Champion points:

Blue:

Put most points into Mighty, then spread out between Thamaturge and Precice strikes. 1 or 2 cp can be placed in Piercing for the "bang for the buck", but we don't need much more since we have so much armor reduction debuffs with corrosive armor, fire breath and night mother (which is my favorite setup).

Red:

Make sure to have 120 points in lady for the Unchained passive. For example 50 in Hardy, 50 in elemental defender and 20 in Thick skinned, or whatever you prefer.
Have some points into Quick recovery for more healing from vigor, blood craze and Battle roar.
I also have rest of my points into Medium armor focus and Spell shield.

Green:

Have most points into Warlord and Mooncalf. But put some into Sprinter and Tumbling too, since you actually sprint, break free and roll dodge constantly in arena. This is your main defense and also your gapcloser.

General playstyle:

Buff yourself up with whatever you have time for, priority igneous wepons, then volatile armor then evil hunter. Hold a charged bow attack followed by poison injection and burning breath on bigger mobs. Weapon swap and use rapid strikes first. If mobs are far from dead, put blood craze on for the extra dot dmg, low cost and some incoming healing.

Don't be afraid to use corrosive armor ultimate. Its good stamina return when used. You always need stamina in your pool. If you have 500 ultimate saved up, you are saving it too much. But its nice to have on final bosses.

Your main defense are your roll dodging. Roll dodge and swap to bow bar for speed buff. No gapcloser needed. After I break free, I usually press vigor and a roll dodge animation cancel. This is a very good defense thing to do, and will save lives.

Especially for Flawless, use every sigil possible. Dont stack defense and healing sigil. Wait 30 seconds between each. Use power sigils on bosses. Speed sigil is nice overall, since we use our speed as a gapcloser.