During the course of the main story, you'll have visited everywhere in Alola, except for the east side of Poni Island. Now that you're the Champion, it's time to conquer these last uncharted lands.
To get started, head east from the central crossroad in Ancient Poni Path. As soon as you start making headway, you'll be stopped by the Kalos duo who want to show you their new toy.
Pokemon Trainer Dexio
His first Pokemon Espeon is a hurdle in itself, with high Speed and special stats. Besides a powerful STAB Psychic, it has Ghost and Fairy-type moves to mess up advantageous Types. However it has poor HP and Defence, so an easy KO... if you can survive.
Alolan Raichu is in a similar boat as Espeon; it's quick and strong, but not very durable. Because it's part Electric, it's weak to Ground moves on top of Bug, Dark and Ghost. Unlike Espeon, it has no coverage moves, but can use Light Screen and Reflect to support its allies.
Slowking is one of two possible evolutions of Slowpoke. Compared to his homely bro, the king boasts superior Special Defence, although its Defence is still decent. Of course, it's still slow as heck. Dexio's has Psychic, Rock, Ice and Fire-type moves, but oddly no Water ones.
Metagross is the final evolution of Beldum, a physical powerhouse with good all-round stats, but average Speed. It's weak to Fire, Ground, Dark and Ghost-type moves. Dark-types need to watch out for Brick Break though and be cautious of its Bullet Punch, a priority move.
Finally, his trump card is his Alakazam that Mega Evolves on the first turn. Mega Alakazam has frightening Special Attack and Speed, but poor HP and Defence. This one knows Focus Blast to punish Dark-types and Energy Ball because why not? You'll want something strong like a Legendary.
Fend off Dexio's Mega Evolved Pokemon and you'll earn the rights to use Mega Evolution yourself. You'll be given a Key Stone that can trigger Mega Evolution in battle an an Alakazite Mega Stone to Mega Evolve Alakazam. The other Mega Stones you'll have to find yourself.
When a Key Stone is available and a compatible Mega Stone is held, you can make a Pokemon Mega Evolve mid-battle by tapping the "Mega Evolution" button to the left of the Pokemon's moves.
Mega Evolution allows Pokemon to achieve better stats and often a new Ability or Type. Unlike traditional evolution, Mega Evolution is not permanent and ends after the battle is over. Like Z-Moves, you can only Mega Evolve once per battle.
Once the holidaying pair are gone, carry on east, then follow the path around towards the north. At the far end, between the red-brick walls is the exit leading to Poni Grove itself.
By the way, if you're struggling to defeat any of the postgame trainers, you can actually reach Poni Grove without bumping into Sina and Dexio. To do so, glide to Poni Breaker Coast. From there, you can head through the brick wall path without coming from the central crossroad.
Pokémon Encounters - Poni Grove
|Name||Type||Location (Encounter Rate)|
|Raticate*||Dark/Normal||All grass (30%, Night only)|
|Pinsir||Bug||All grass (10%)|
|Granbull||Fairy||All grass (20%)|
|Riolu||Fighting||All grass (10%)|
|Trumbeak||Normal/Flying||All grass (30%)|
|Gumshoos||Normal||All grass (30%, Day only)|
|Lucario||Fighting/Steel||(SOS only) Possible ally Pokemon for Riolu|
|Chansey||Normal||(SOS only) Possible ally Pokemon for Riolu|
Originally, a Veteran was blocking the way beyond, but he's no longer there. Step into the tall grass ahead, then follow the path between the grass as it snakes towards the north. To the east, there's a trainer looking for a scrap. If you prefer, you can sneak past him from the west side.
Black Belt Roy
East from Roy is a Max Potion on the other side of the tall grass. After pocketing it, continue heading north. Towards the north-west corner, grab the X Sp. Atk sitting behind the grass. It can be hard to see during the day, but in the corner of the cliff above is a Zygarde Cell (83) .
From here, head in an easterly direction, away from the tall grass. Unless you're looking for wild Pokemon--which isn't a bad idea. Once you've gone around the corner, there's a trainer wandering around towards the east, two patches of tall grass away.
Ace Trainer Jackson
Alolan Marowak you may not have seen for a while. This regional variant is weak to Water, Rock, Ground, Dark and Ghost-types.
Finally, Braviary is weak to Electric, Rock and Ice-types. All in all, nothing that should cause a Champion to break a sweat.
After this, the exit to the next area is just up ahead. Before leaving though, look around the east-most corner of the area for another Zygarde Cell (84) that's hard to see in the bright daylight.
The wild Pokemon here are all fairly formidable, but mostly ones you've seen before. Riolu is the only new Pokemon, a Fighting-type that evolves into the powerful Fighting and Steel Lucario.
If you're patient, you can encounter Lucario as an ally Pokemon when Riolu is in danger. Otherwise you just need to boost Riolu's Happiness to make it evolve during the day.