Are you sure they're Dragons, and not Humanoid (Dragon)?
Probably i'll play a baaz draconian pc in a Dragonlance campaign and i would like to use Disguise Self magic to hide my appearance.
But Disguise Self state "You cannot change your creature type (although you can appear as another subtype)" and draconians are Dragon type.
Therefore am i not able to use Disguise Self to change my appearence in an Humanoid creature?
We have the same problem with tiefling and aasimar, who are outsider, despite being very similar to humaniods.
By raw you can't change into humanoid creatures, but I think it is very reasonable to allow it, as it makes more sense, than a creature who are mostly human, suddenly turn into a replica of a dragon or a balor.
Probably i'll play a baaz draconian pc in a Dragonlance campaign and i would like to use Disguise Self magic to hide my appearance.
But Disguise Self state "You cannot change your creature type (although you can appear as another subtype)" and draconians are Dragon type.
Therefore am i not able to use Disguise Self to change my appearence in an Humanoid creature?The text refers to the fact that your creature type does not change as to how spells affect you. So yes you can use Diguise Self to give the desired appearance.
Remember the spell is illusionary only so anyone who makes contact with you gets the saving roll to disbelieve.
I disagree on the first part. The text does not refer to the fact that your type doesn't really change (which is not possible by any spells). The text states "You cannot change your creature type (although you can appear as another subtype)". The although in the latter part of the sentence, indicates clearly that you can appear as another subtype but not another type.
The spell does not allow you to take the appearance of an animal, outsider, or any other creature that does not belong to your type.
By the RAW you would not be able to take another humanoid shape, however I think you can still cast the spell to aid your disguise making you a 'dragon' or draconian as close to human as possible within the spell. You will have to take into account the -2 modifier to disguise yourself as a different race and possibly another -2 since draconians are genderless I think. This will still give you a +6 bonus on disguise for casting the spell.
In my opinion everything that is a fair use of the disguise skill is possible with the disguise self spell.