Is it time to reveal another one of my favorite offensive cores? Yes, it is.
Tyranitar @ Choice Band | Sand Stream
Adamant | 156 HP / 252 Atk / 100 Spe
Crunch | Pursuit | Stone Edge | Superpower
Keldeo @ Choice Scarf | Justified
Timid | 252 SpA / 4 SpD / 252 Spe | 2 Atk / 30 Def
Hydro Pump | Secret Sword | Hidden Power | Surf
Latios @ Choice Specs | Levitate
Timid | 4 HP / 252 SpA / 252 Spe | 0 Atk
Draco Meteor | Surf | Psyshock | Trick
This core of three revolves around the powerful attacks the three can throw around, as well as the incredible synergy their typings are responsible for. What are the only Pokemon that can stop Scarf Keldeo from ripping teams apart? Celebi, Starmie, Latios, Latias, Slowbro / Slowking, Amoonguss. What do they all have in common? A vulnerability to CBtar's Pursuit and Crunch. After a Pursuit / Crunch from Tyranitar, the aforementioned Pokemon should either be KOed or in critical condition, unable to take an attack from Keldeo.
The third member of this core, Latios, is meant to serve as a more reliable counter to Amoonguss, as well as a wall-breaker and check to opposing Keldeo. It also helps that Latios gives trouble to sun teams, many of which cannot take a Specs-boosted Draco Meteor once their Heatran and / or Forretress have been weakened, a task which Tyranitar and Keldeo excel at. Sheer Force RP Landorus, a threat to Tyranitar and Keldeo, is also handily checked by Latios.
Now, despite how good this core looks, it does have its fair share of problems. For instance, offensive LO Volcarona is public enemy
numero uno. It can grab a boost against Latios and Keldeo locked into the wrong move and proceed to wreak havoc against the core with its Fire / Bug STAB, and if it opts to use Giga Drain, then Keldeo cannot be used as a counter. Bulky variants can actually stomach a non-boosted Hydro Pump at +1 and continue to set itself up. SD Lucario is another problem if Keldeo and Latios have been weakened, since it can run through the core after a boost and prior damage on the two. Opposing Dragons are also a problem, necessitating the use of a Steel-type to help beat them down. Offensive SD Scizor is a problem if it can set itself up.
As for teammates that support this core, Heatran seems to have worked as a great partner, since it deals with the issue of Volcarona, Scizor, and Dragon-types rather effectively. Also, if you use certain Heatran sets, then Heatran can also be used to provide SR support. Powerful late-game sweepers, such as SD Techniloom, Sheer Force Landorus, and Terrakion among others, also appreciate the strength this core brings, allowing them to clean up house in the end-game. All in all, while this core may have some problems, I think that it is a rather solid offensive core that does well against the majority of what is thrown at it.