In a certain point of the game the Romun Empire will invade Port Rimorg town, Later Emilio will notice that his Pikkard are vanished and it's up to you to find them and bring those cute furballs to him, here's where you can find them:

The first pikkard is the easiest one to find, he's at Windseeker Heights it's impossible to not find him, here's a picture of the location (i already picked up the pikkard in this screenshot)

The second Pikkard is In the Ruins of Amnesia, simply Teleport in the "Depth" zone, you'll find the Pikkard right next to the save point

The Third Pikkard is in the peek of the Grana-Vallis Mountain, Teleport to the "Peek" zone and take the path on the right of the savepoint, you'll find the Pikkard in the zone right before where the Crab Boss Battle happened.

The Forth and last Pikkard is at the Sunrise Inlet, where you meet with Dogi and the Other Pirates again, the Pikkard is on the right of the zone, just pick him up and go back to Port Romorge, Emilio will give it to you the Daylight stone, an accessory that will revive you in case you'll get Defeated, but it will only work once.

Have Fun!