I don't understand what ur trying to say here but Celebi and Starmie are better counters to Keldeo than Gastrodon. Celebi can come in on almost any of Keldeo's attacks except the uncommon HP Bug and OHKO with Leaf Storm. Same goes to Starmie although it gotta be more careful because of weaker defenses; Starmie can still OHKO with T-Bolt. Both have reliable recovery in Recover.
Please tell me how Starmie is a counter, it is a check (*shudder*): Starmie Outspeeds the specs, sub CM and offensive CM sets, but
DOES NOT OHKO without prior damage.
252 SpA Life Orb Starmie Thunderbolt vs. 4 HP / 0 SpD Keldeo: 247-291 (76.23 - 89.81%) -- guaranteed 2HKO
Scarfdeo outspeeds Starmie regardless too.
Also:
252 SpA Choice Specs Keldeo Hidden Power Ghost vs. 0 HP / 4 SpD Starmie: 260-306 (99.61 - 117.24%) -- 93.75% chance to OHKO
252 SpA Choice Specs Keldeo Hydro Pump vs. 0 HP / 4 SpD Starmie: 166-196 (63.6 - 75.09%) -- guaranteed 2HKO
Not reliable, not to mention that Starmie is very frail to reliably use Recover a lot.
Not to mention, what is Starmie going to do against a Keldeo with either a sub up or a CM?
252 SpA Life Orb Starmie Thunderbolt vs. +1 0 HP / 4 SpD Keldeo: 164-195 (50.77 - 60.37%) -- 89.45% chance to 2HKO
And guess which move Keldeo commonly runs? HP-Ghost, yeah: Gastrodon does it better. Sure Keldeo still threatens it, but what does Keldeo not threaten? Not to mention the ability to nullify Keldeo's strongest stab is a huge plus.
Calcs with Keldeo vs Standard Defensive Gastrodon with EQ:
252 SpA Keldeo Secret Sword vs. 252 HP / 84 Def Gastrodon: 169-201 (39.67 - 47.18%) -- guaranteed 3HKO
252 SpA Choice Specs Keldeo Secret Sword vs. 252 HP / 84 Def Gastrodon: 253-298 (59.38 - 69.95%) -- guaranteed 2HKO
0 Atk Gastrodon Earthquake vs. 0 HP / 0 Def Keldeo: 102-120 (31.57 - 37.15%) -- guaranteed 4HKO
0 Atk Gastrodon Earthquake vs. 4 HP / 0 Def Keldeo: 102-120 (31.48 - 37.03%) -- 82.96% chance to 3HKO
Please tell me how Starmie does it better than Gastrodon.
However, both have very different roles: the only thing they have in common is a water-typing, other than that. It's pretty much comparing apples and pears.
Also, about Celebi:
0 SpA Celebi Giga Drain vs. 4 HP / 0 SpD Keldeo: 176-210 (54.32 - 64.81%) -- guaranteed 2HKO
252 SpA Keldeo Hidden Power Ice vs. 252 HP / 232+ SpD Celebi: 112-132 (27.72 - 32.67%) -- possible 4HKO
252 SpA Keldeo Hidden Power Bug vs. 252 HP / 232+ SpD Celebi: 224-264 (55.44 - 65.34%) -- guaranteed 2HKO
and with bug becoming somewhat more popular, you can hopefully see where this is going. Also, please tell me when it has been a good idea to use leafstorm over giga drain, maybe I'm just too passive a player: I don't know.
However, Sp. Defensive Celebi is and will be the best counter to Keldeo w/o Bug, but Specs HP-ghost comes 'close' to beating it:
252 SpA Choice Specs Keldeo Hidden Power Ghost vs. 252 HP / 232+ SpD Celebi: 168-198 (41.58 - 49%) -- guaranteed 3HKO
However this is all pure theorymon, prior damage, hazards and weather haven't even been factored in: because I'm lazy like that.