Victini Analysis
Victini is a cool poke and can be deadly when handled properly in a battle. It has 100 base stat on each category (hp,sp.atk.speed etc.). It has access to T-bolt which covers its water weakness and can also help deal with bulky flying types like Mandibuzz. It's a pretty strong poke but do keep in mind it's not unstoppable. There are many pokes out there that can easily counter Victini such as Heatran and especially Dragon types which resist Victini's Fusion Bolt, V-create etc.
Victini only has one ability which is: Victory Star
Physical Attacker: Adamant/Jolly 252 evs on attack and speed Item: Choiceband/Lifeorb
Move1: Fusion Bolt - to deal with water types
Move2: V-create - Victini's sig move with a massive 180 base + Stab
Move3: U-turn - to deal damage against the ever common Tyranitar and to scout
Move4: Zenheadbutt - Stab+to deal with the likes of Conkeldurr
Special Attacker: Modest/Timid 252 evs on sp.attack and speed Item: ChoiceSpecs/ChoiceScarf/Lifeorb
Move1: Thunderbolt - to deal with water types
Move2: Searing Shot - Stab
Move3: FocusBlast - to deal with Hydreigon and other dark types which is Victini weak to
Move4: Psychic - 2nd Stab and also to deal with the likes of Conkeldurr
TrickRoom: Quiet 252 evs on hp and sp.attack
Move1: FusionBolt - to deal with bulky water types such as Lapras,Milotic,Slowking etc.
Move2: V-Create - Victini's sig move and Stab
Move3: Psychic - stab and to deal with Conkeldurr and other fighting types
Move4: TrickRoom - self explanatory
*Focusblast wasn't in the set as dark types aren't really that common and I was debating whether which one of Psychic and FocusBlast should be replaced with TrickRoom and I went for FocusBlast. As I said dark types aren't common and Psychic gets stab.*
Good Counters against Victini
Cincinno, Hydreigon, Altaria, Clefable, Chandelure, Gengar, Donphan, Lanturn