Sorry I can only give in english.  An alliance is usually "stronger" than a NAP and each alliance will explain their specific benefits and responsibilities. My clan is in an alliance (we actually started it) where we all are committed to not attack our own kingdom members unless continuously provoked.  We do not have the responsibility of "defending" all clans in the alliance against attack, where as some alliances that is their main purpose.   

If you have examples of agreements within an alliance, please share !

Thanks !

Alliance is where you can exchange RSS, Equipment like if u have some SH equipments unlocked and your ally has some other ones unlocked then you dont have to worry about the ones they have and you dont have..just go there when you have all legendary stuff ready to make that equipment legendary and make it. Ally also support you when you are at war and also you have to support back. There can also be some player exchange and also Repute Exchange if you have POP. But always keep your players first then them. But be Careful in choosing Ally many times Back-Stabbing occurs and that would crush moral of your players.