Another day, another demon. This time, it's a giant combat frog with poor hygiene.
Hezrous are fairly decent regarding base stats. Their constitution is almost balor- and glabrezu-levels high, their strength is not bad, and their other stats range from 10 to 18. Hezrous are large-sized and enjoy 10 feet of reach as a result.
For natural attacks, Hezrous have two claws and a bite. The claws deal 1d8 base damage, the bite 4d4, so I recommend wielding a two-handed weapon in your claws. Hezrous should be able to wield weapons: the first Fiendish Codex shows one holding a chain with little apparent difficulty.
Spell-likes are a bit thin (by tanar'ri standards), with three abilities usable at will and and two thrice per day. Your at-will abilities are Chaos Hammer and Unholy Blight as well as Greater Teleport, which should be mostly useful if you're faced with enemies at range. I can't see them winning encounters or solving difficult challenges, though.
The limited SLA's are Blasphemy and Gaseous Form. Gaseous Form isn't that useful when you can teleport at will, but it may help you get in dimensionally locked places. Blasphemy is quite useful when you get it, but monster HD will begin to outstrip its fixed CL quickly.
Finally, there's two additional abilties. Stench, while kind of ridiculous (fear the power of my bad body odor!) is essentially a free save-or-suck against all nearby creatures. It's a pity poison immunity stops it. The summoning of either another hezrou or a horde of dretches may be useful, but the low rate of success is too bad.
All in all, Hezrous possess several useful abilities, though they don't approach the level of power possessed by other demons. +1 LA seems about right.