in Pokemon heartgold go north from olivine city you should see a farm go in it and feed miltank oran berries than talk to the girl on the right side she will give you a seal case.
U get it at the right of solaceon
You will meet a kid that is in the Solaceon Ruins that will tell you to go to his house. His house is in between Solaceon Town and the Solaceon Ruins. You talk to his mom and she will give you the Seal Case. P.S. Talk to the kid kid and he will give you some things for the Seal Case.
In solaceon town, go to the old lady's house which is in the east, talk to her and she will give you the seal case.
First you go to Solaceon Town. Go in the ruins an you met a little boy, When you'r out the ruins, there are some houses next to the cave, in 1 of the houses are that boy and his mother. Talk to the mother and she gives you a Sealcase :)
No you do not need to help the miltank it is recommended though. You need to give it 7 oran berries then you will get a Seal Case and some seals. Which can customize the way your Pokemon enters the battle.
You can find the Seal Case by feeding the Miltank Oran Berries at Route 39
U get it at the right of solaceon
Y
You can find a seal case in sunny shore city. You talk to the guy in the top left corner of the seal market.
You will meet a kid that is in the Solaceon Ruins that will tell you to go to his house. His house is in between Solaceon Town and the Solaceon Ruins. You talk to his mom and she will give you the Seal Case. P.S. Talk to the kid kid and he will give you some things for the Seal Case.
in a house near the ruins
talk to little boy in salaceon ruins. go to his house his mom gives u a seal case
You can find a seal case in sunny shore city. You talk to the guy in the top left corner of the seal market.
Egg case? There's no egg cases but there is a coin case, seal case,fashion case and poffin case.
In the MooMoo Farm on Route 38, give the miltanks oran berrys to heal them, and one of the girls will give you a seal case.
It's in Solaceon Town. You have to talk to the boy's mother. She and her son live in one of the houses by the foresty part in the town.
It is not possible to get the Seal Bag in Pokemon Diamond. The Seal Bag currently has no use and is likely something left over from development. It possibly used to have the same role as the Seal Case but got changed during development.