Magic Items for Fiend of Possession

[Yogibear41]

Looking for suggestions for magic items for a fiend of Possession cohort.

Plan for the fiend to spend the majority of its time inside the sword of another character to give it bonuses, but I may have it do ethereal scouting from time to time.

Since the only things I can think of that can affect it while it is inside an object are will save based, items to boost that save are a given.
Other than that the only things that I believe that can affect it are force effects and gaze attacks (while it is ethereal only) So I would like to shore up weaknesses against those attacks. The character also has minor cleric spell casting (2nd level and lower spells only) if that changes anything.

[Segev]

Out of curiosity, what's the cohort's build? What's the base fiend?

As for magic items...

IT really depends what you want them to do. They basically give profane bonuses to items; can they give stat enhancements without possessing you?

You probably do'nt need a specific one. Just pick something you already own and use, and have him move if you get rid of it or use something else more often.

[Yogibear41]

Oh no no no, not items for the fiend to possess, Magic items for the fiend Itself to wear. Right now I have it down as having a vest of resistance for example to boost its well saves vs things like holy smite/dismissal.

As far as the fiend itself.

I am using a Sun Elf with the otherworldly feat to make it an outsider, with a third party +1 la template thrown on that gives it the Evil Subtype. Got some fluff in the backstory involving reincarnation that makes it all fit together story wise, but that is the crunch.

ECL 10: (+1 la bought off)

Cloistered Cleric 3/Church Inquisitor 1/Fiend of Possession 4/Bloodline levels 2.

Church Inquistor requires LG/LN, character is LE, but that will be a "pre-fall" type scenario.

I might tweak the build to be honest, just trying to boost that will save up without losing casting levels. If I find another prestige class that works I can use that.

[Segev]

The main items it would need are stat boosts for its DC-determining stats, I think. It's going to be hiding in items most of the time, right?

Maybe active items that let him do utility tricks. Something to maximize his spot/search/listen prowess so that he is a good second set of eyes.

[MaxiDuRaritry]

Not a magic item, but take the Wedded to History (Survivor) feat. Since you plan on boosting the Will save sky-high, that means his other two saves will suffer when he actually has to make one or the other. So why not use Will saves for everything? Also, get Mettle for Will save evasion.

As soon as you can get one, a psychoactive skin of proteus. Then he can become an item whenever he needs to. How about a few scrolls of hardening, a tooth of Leraje, and a soul crystal of matter manipulation at the highest ML you can afford, along with some quintessence? All of them grant hardness (which mostly stack with each other), meaning whatever item he inhabits will have crazy good defenses.

Since most arcane and divine spells require things he can't use while inhabiting an item (material/verbal/somatic/focus/divine focus components, mainly), try focusing on psionic stuff, since that's mental only (except for a few stupidly written powers, such as energy ray). The aforementioned psychoactive skin could be worn over whatever item he's inhabiting, allowing him to shapeshift into whatever tool or weapon or creature he likes. If his body is damaged, he can use the skin to heal it. If it's destroyed, he can simply take the skin with him and reinhabit another item.

As a cheaper version of the skin, how about a morphing/sizing/metalline/eager/warning +1 aurorum arrow with a ton of really cheap but powerful enhancements on it? Then he could inhabit it as the world's greatest multitool. If it's sundered, he can just fix it like the world's most powerful jigsaw puzzle.