This is my first question, so forgive me if I seem to miss some of the protocols. I'm running a D&D 3.5 custom campaign setting, I tend to be a "low magic" and very high rp kind of guy focusing more on narrative and character development than hack and slash play styles, and, I've been a DM for a few years now, I have reasonable experience, but I've basically stuck to my guns (and thus have not experienced a lot of interesting sides to the game), I'm running a campaign with my most regular group now to break molds and try things we've never done before.
They are all either Dwarves or Gnomes (4 or 5 players depending on who shows up on a given week) who are on a massive expeditionary quest to find an ancient dwarven city that has sunk into a place very much like the "Lowerdark" of Forgotten Realms. The group is all level 5 currently and I'm wanting to use an item I've never had a chance to use. An intelligent magical warhammer who calls itself "Kashte'dun" and it was built during a time when the dwarven empire was losing a lot of territory, it has the special purpose of reclaiming lost dwarven territory, it is lawful neutral and as a rule of thumb (but not an actual guideline) it will usually only choose a dwarven wielder, the exception being any character of a race could wield it if for whatever reason they are on a mission that would coincide with reclaiming dwarven ruins as that is the main perrogative of the hammer. That all aside, I have a level 5 dwarf barbarian, ranger (two-weapon currently with urgrosh), bard, and rogue and a gnomish cleric to consider. Being that they are level 5 and 9 times out of 10 this hammer will be used by one person:
What should the hammer be capable of? IE Max Modifier Bonus, What kinds of lesser abilities? any greater abilities? Of course it has a specific purpose and a dedicated ability of some kind. And what should its attributes be? (I believe it should have high wisdom and charisma at the sacrifice of intelligence if need be)
Furthermore, what is a fair way to determine who gets it? I have never dropped such a valuable item to be covetted by an entire group. Should I perhaps find a way that it uses each player to further its goals at some point usually sticking with the preferred host? Should I add in less flashy but just as useful magic weapons and armor to take the edge off for the other players and have the hammer just stick with whoever fits it?
And one last question, I need some kind of subtle "escape hatch" for it. Incase it ends up over-powered, abused, out of place, etc. Some way it can leave without everyone feeling the sting of losing an item like that (perhaps if it's abused it has a failsafe that makes it kind of self-destruct, leaving it devoid of its intelligent properties and just a "+blah warhammer")