It would be great if you can add more depth into your descriptions and maybe a bit on team building and the general idea behind the team, otherwise the mods might have to lock it until its modified. Usually when people rate they suggest team member replacements along with their usual analysis, but I want you to go through with the same team with better sets so you can get a better feel of the meta before coming back:
Greninja (M) @ Life Orb
Ability: Protean
EVs: 4 HP / 252 SpA / 252 Spe
Timid Nature
- Surf
- Dark Pulse
- Hidden Power [Ground]
- Ice Beam
There are 3 common OU electrics, Thundrus-I, Rotom-W and Mega Manentric (there seems to be a rising acknowledgement of Assault Vest Raiko). You might save yourself from T-Waves but otherwise it won't hurt Thundrus, Rotom-W is immune as well and Mega Manentric can only be hit first in his base form or the first turn he MEVOs, so yeah.
It is best to give Greninja as much coverage and fire power as possible, so I suggest the following (standard set):
Greninja (M) @ Life Orb
Ability: Protean
EVs: 4 SpD / 252 SpA / 252 Spe
Timid Nature
- Surf/Hydro Pump
- Extrasensory
- Hidden Power [Grass]
- Ice Beam
HP Grass OHKOs your common Greninjas, 2HKOs Rotom-W and Thundrus would be faced with a death choice if he decides to T-wave you infront of Ice Beam. Hydro Pump is your main weapon, hits everything hard and in general is worth the acc drop. Extrasensory hits Keldeo and Gengar hard and Ice Beam rounds the coverage and deals damage to Flying folks and Dragons.
Tyranitar (M) @ Tyranitarite
Ability: Sand Stream
EVs: 252 HP / 252 Atk / 4 SpD
Adamant Nature
- Stealth Rock
- Stone Edge
- Crunch
- Earthquake
Switch the nature to Jolly (outspeeds base 130s at +1) and SR for DD as has been suggested before me. A good replacement for EQ is Ice Punch which OHKOs a 252 HP Landrous-T and Gliscor at +1.
Volcarona (M) @ Lum Berry
Ability: Flame Body
EVs: 128 HP / 142 Def / 96 SpA / 144 Spe
Modest Nature
- Quiver Dance
- Fiery Dance
- Morning Sun
- Bug Buzz
Use Giga Drain over Morning sun and a standard offensive spread of 252 SPA/252 Speed/4SpD. If you want a bulkier version with reliable recovery:
Volcarona (M) @ Leftovers/Lum Berry
Ability: Flame Body
EVs: 240 HP/252 Def/16 Spe
Modest Nature
- Quiver Dance
- Fiery Dance
- Roost
- Bug Buzz
From the dex:
"The EVs and Timid nature allow Volcarona to outspeed Jolly Breloom unboosted, base 130 Speed pokemon after 1 boost, and everything after 2 boosts. The rest is put into Defense and HP to let it get as many boosts as possible. The HP EV's allow it to take less damage from Stealth Rock so it can switch in twice, and Defense is maximized. Flame Body is useful to have a chance of burning physical attackers."
Forretress (M) @ Leftovers
Ability: Sturdy
EVs: 240 HP / 8 Atk / 220 Def / 40 SpA
Relaxed Nature
IVs: 0 Spe
- Hidden Power [Ice]
- Gyro Ball
- Rapid Spin
- Explosion
SR instead of HP Ice as been suggested. You can put the EVs in SpA back to Def.
