1.Build and explanation why I chose each skill.

BUFFS

Increases m.def by 546 and LP by 1666. Always try to cast this skill first
Increases e.atk by 18%. Helps SK to deal serious dmg Always try to cast it right after Draconic Protection.
Additional 19CON is very important in reflect based strategy against speed fighters. Cast it as third skill
Very good SK buff which gives additional 25% anty-crit. With good gear and event boss title SK can reach 75% anty-crit.
Immunity to fear and confuse. Very useful. The only problem is long CD.

DEBUFFS

Paralysis the target for 7sec (with RP it lasts longer). Very useful as it gives us time to start some nice combo.
Lowers target m.def and e.def by 557. Good to start with cause it increases amount of damage we deal to the target. ALWAYS try to cast it!
It's not debuff but it suits this category. ArmPull can be used to begin nice combo like: Go to the edge->ArmPull->Draconic Overpowering (RP-increase duration)->dash behind opponent-> KD/Fear out of the arena.
Nasty skill when combined with MysticAttack. Your opponent might has full +15 gear but if isn't eqquiped with anty-fear accesories he's done.
Only reason i picked this skill is after putting 1SP we can set RP to KD. Skill works like QA from MA's tree. Dash to opponent and KD him (if RP is used). Useful skill against Cranes and Turtles.
Good skill so start battle with. Has 45m range and stuns target for 5sec. Enough to cast buff or two.

ATTACKS

The strongest SK attack. Deals a lot of state damage (if axe is highly upgraded) and makes target bleed. You can one shot unprepared human with this skill.
Has long animation but game treats this skill as debuff therefore it's based on success rate and fighters can't dodge it (unless they use resistance rate gear)
Second OP SK skill. It's based on physical damage therefore it's perfect against e.def geared opponent. It deals dmg to your opponent and at the same time heals you. Very good when you want to win by time out. Important!. This skill ignores your enemy %LP regen.
Nice debuff which deals dmg whenever your opponent will cast skill. Like StealLife it ignores your enemy %LP regen.

My PvP build looks like THIS

2. Gear used while facing each class.

FIGHTER
Jacket: %Anty-crit (m.def)
Pants: %LP (m.def)
Boots: %phy reflect (m.def)
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: 2x %phy reflect / FOC pair from BID4 (17FOC + 13%phy reflect)
Earrings: 2x props
Necklace: success rate
SWORDSMAN
Jacket: %Anty-crit (m.def)
Pants: %LP (m.def)
Boots: %phy reflect (m.def)
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: 2x %phy reflect / FOC pair from BID4 (17FOC + 13%phy reflect)
Earrings: 2x props
Necklace: success rate
TURTLE HERMIT
Jacket: %Anty-crit (e.def)
Pants: %LP (e.def)
Boots: CON / %movement speed
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: CON pair from BID4 (17CON+15%ene reflect and 30 resistance rate)
Earrings: 2x props
Necklace: %paral time decrease
CRANE HERMIT
Jacket: %LP (e.def)
Pants: %LP (m.def)
Boots: CON / %movement speed (e.def)
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: 2x %decrease bleed duration
Earrings: 2x props
Necklace: %decrease bleed duration
SHADOW KNIGHT
Jacket: %LP (m.def)
Pants: %LP (m.def)
Boots: CON / e.reflect (m.def)
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: 2x %decreases paral and fear
Earrings: 2x % decreases bleed and fear
Necklace: %decrease bleed and paral duration
DARK WARRIOR
I haven't seen DW in Budokai so no gear needed
DENDE PRIEST
Jacket: %LP (e.def)
Pants: %LP (e.def)
Boots: %ene reflect
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: FOC pair from BID4
Earrings: 2x props
Necklace: %dmg of your weapon prop
POKO PRIEST
Jacket: %LP (e.def)
Pants: %LP (e.def)
Boots: %ene reflect
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: FOC pair from BID4
Earrings: 2x props
Necklace: %dmg of your weapon prop
ULTIMATE MAJIN
Jacket: %LP (m.def)
Pants: %LP (m.def)
Boots: %phy reflect
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: FOC pair from BID4
Earrings: 2x props
Necklace: % decrease candy duration
GRAND MAJIN
Jacket: %LP (m.def)
Pants: %LP (m.def)
Boots: %phy reflect
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: FOC pair from BID4
Earrings: 2x props
Necklace: % decrease candy duration
PLASMA MAJIN
Jacket: %LP (e.def)
Pants: %LP (e.def)
Boots: %ene reflect
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: 2x %decrease confusion duration
Earrings: 2x props
Necklace: % decrease confusion duration
KARMA MAJIN
Jacket: %LP (e.def)
Pants: %LP (e.def)
Boots: %ene reflect
Gloves: FOC (e.atk)
Axe: %ene crit
Rings: 2x %decrease confusion duration
Earrings: 2x props
Necklace: % decrease confusion duration

3. Strategy for beating opponents.

Note: Tactics listed below apply to avarage players. This part only shows you direction. The exact way to become WMAT Champion you will have to find yourself.

Throwing out of the arena: This strategy works for every class but only if you have good ping. It goes like this: Dash to the edge->ArmPull->Paralys (RP-Duration)->Dash behind enemy->KD/Fear. However it's a little bit risky cause when you dash to the edge other player may throw you out so you need to be very carefull using this tactic.

FIGHTER
Generally SK don't have to do anything. Fighter kills himself because of reflect and if he is still alive after his attack than use HellzoneGrenade or StealLife and you won. Gear is very important otherwise fighter will one shoot you.
SWORDSMAN
The same story as fighter. The only difference is that SM spamms KD so at the begining of fight I advise to dash to the center of arena.
TURTLE HERMIT
Turtle like SM also spamms KD and try to win by throwing enemy out of the ring. Again at the begining dash to the center than use ChargingFist or and the rest is up to you. Either you can throw/fear him out or just kill using LifeSteal, HellzoneGrenade, Curse or BoldStrike
CRANE HERMIT
Without high %anty-bleed you can surrender. But if you have it than work like with turtle.
SHADOW KNIGHT
The most OP class in whole game. Figt SK vs Sk is quite interesting. First try to throw SK out. Second win by having more %LP at the end or Third kill SK. If SK will use Curse change your rings to e.reflect and enjoy the show. If you cant throw your enemy out than try to kill him using LifeSteal (if he doesn't use m.def he is done) BoldStrike with RP seted to increase bleed duration and spam HellzoneGrenade.
DARK WARRIOR
Never seen DW in Budokai therefore I don't have any specific tactic.
DENDE PRIEST
Well since Dende has strong healing skills I advise to fully charge RP and than use Draconic Curse->Draconic Roar (Dende has skill which delete last casted debuff so by casting this skill you prevent him from taking off Draconic Curse)->StealLife->ViolentSlice (RP-duration)->BoldStrike (RP-CD)->Curse->Fear (RP-duration)->again BoldStrike->HellzonGrenade. Eventually if Dende is still alive you can use HTB and HTB2.
POKO PRIEST
Strategy is very similar to one vs Dende Priest.
ULTIMATE MAJIN
Well peoblem with Ulti is that it has buff to increase %LP by 21. You need to remember that Ulti can cast a skill which delete the latest debuff so before castin Draconic Curse use Draconic Roar. If Ulitmate has anty-fear accesory than spam StealLife, BoldStrike, Curse and HellzoneGrenade. If enemy has anty-bleed than fear him out.
GRAND MAJIN
Strategy is very similar to one vs Ultimate Majin but cause Grand has weaker buffs you can try to kill him.
PLASMA MAJIN
Annoying class cause of spamming KD. You can use earring quest which increases chance to avoid KD. When you have oportunity use Draconic Overpowering than LifeSteal->Curse->BoldStrike (RP-CD and HellzoneGrenade.
KARMA MAJIN
Because Karma has Shout (stun with 45m range) it will begin fight and than use Hesitation (prevents from using skills). While Hesitation you can use HTB,HTB2 and GreatNamek. These three skills combined with reflect and LifeSteal, Curse and BoldStrike should be enough to kill Karma. If you decide to use HTB than do this right after Karma's Hesitation cause than skill is on CD and you can finish opponent.

1.Build and explanation why I chose each skill.

BUFFS

Increases m.def by 546 and LP by 1666.
Increases e.atk by 18%. Helps SK to deal serious dmg
Additional 19CON
Very good SK buff which gives additional 25% anty-crit. Always use to prevent being one shot by boss or ultra.
Must have for PvE. Increases dmg and %attack speed. At lvl 3 EP and LP is very little so our Healer wont have any problem.
Very, very important SK skill. Increases generated aggro by 1000. For those who dont understand I'll explain. let's say SK and Fighter deals 8k dmg to boss. But cause SK used this buff he will attract boss attention cause the game treat his attack like he dealt 10k instead of 7k.

DEBUFFS

Very good AoE provoke skill. Additionaly decreases mobs e.atk by 25%.
Paralysis the target for 4sec (with RP it lasts longer).
Lowers target m.def and e.def by 557. Good to start with cause it increases amount of damage we deal to the target. ALWAYS try to cast it!
When you gather group of mobs run with them to nearest tree/stone and cast this skill. It'll give turtle time to cast Kamehameha. If mobs are still alive cast SelfDestructionWave.
Useful skill when you tank boss. When combined with Turtle's AttackSpeedShackle lowers boss attack speed by 90% (!)

ATTACKS

Just picked it cause it helps to keep aggro when other skill are on CD
Second SK AoE move. With only +8 gloves I dealt 20k dmg at easy. Good vs group of mobs.
The strongest SK attack. Deals a lot of state damage (if axe is highly upgraded) and makes target bleed.
Has long animation but game treats this skill as debuff therefore it's based on success rate.
Second OP SK skill. It's based on physical damage therefore it's perfect against e.def geared opponent. It deals dmg to your opponent and at the same time heals you.

My PvE build looks like THIS

2. Gear needed for PvE.
Every good tank has either 2 sets of armours (one full e.def other full m.def) or highly upgraded one set from crafting. Stats in your gear should be like that:
Jacket: %LP
Pants: %LP
Boots: CON
Gloves: FOC (e.atk) or %e.crit (e.atk)
Axe: %ene crit
Rings: CON pair from BID4 (17CON+15%ene reflect and 30 resistance rate) / FOC pair (17FOC+13%phy reflect) / anty-debuffs
Earrings: 2x props
Necklace: anty-debuffs / %dmg of prop which you have in your weapons / Success rate (wear if you miss taunt skills)