Leatherhead
Possibly a Idiot.
The Mind Whisperer has got tricks by the oodles.
Even though it's not an infiltrator in the purest sense of the word, it is capable of inconspicuous travel via snake form, and boasts a decent enough deception and stealth score to do something with that. You could easily have one set up a "Garden of Eden" situation where it tempts someone with either knowledge or power. Slowly gaining the trust of a young noble, using detect thoughts to grant them their hearts desire, and working their way into influencing the court.
Additionally, they could slither into various areas to assassinate someone, their Mind Fangs power can trigger off of the bite they deliver while polymorphed, making the first trike lethal to lesser npcs, and very painful to any PC of the appropriate levels.
And they could always serve as a leader of the local snake cult.
Another interesting tidbit: They can see through magical darkness. Though they have no way of casting darkness themselves (unless you swap something, and perhaps you should), they can be paired up with a pureblood illusionist or warlock to capitalize on it during combat. Though perhaps you should consider using Fly+ Eldritch blast. I am sure one of your PC's has used that combination at some time or another, and it would be delicious to have them on the receiving end for once.
Now for Malison's in general.
They are the priests and elite warriors of the Yaun-ti.
Warrior Malison's come in 5 different types, 3 from the MM and 2 more in Volo's chapter 2.
Type 1 (snake head) is the archer unit. By coating it's arrows in poison, it deals respectable damage with it's longbow. This is also the type of the Mind Whisperer.
Type 2 (snake arms) is the melee striker unit, it gets to bite twice (though I feel it really should have reach and various poison effects to make it interesting), dealing OK damage, but they don't have hands, so I doubt their general usefulness. I suppose it looks intimidating at least, however you could achieve similar melee prowess by giving one of the other types a Greatsword.
Type 3 (snake lower body) is another melee unit, but has a constrict attack that grapples targets while doing a smattering of damage. It also carries a longbow, just in case, but doesn't coat the arrows in poison (because it has a human head instead of a snake one). I would take them over the type 2's 90% of the time.
Types 4 and 5 share most of the same traits. They are also lower raking than the other Malison's perhaps due to the fact they are not venomous. But at least they have hands and can use weapons, so that's one thing they have over type 2's
Type 4 (snake tails) Should have a tail attack, perhaps with reach, and possibly some kind of knock prone mechanic. But they don't for some reason.
Type 5 (full body snake scales) should have extra natural armor, but again, don't for some reason.
Finally, Malison's have access to all of the Unusual Abilities that Abominations can get from chapter two, giving them a number of additional control options and body modifications to suit their role.
Even though it's not an infiltrator in the purest sense of the word, it is capable of inconspicuous travel via snake form, and boasts a decent enough deception and stealth score to do something with that. You could easily have one set up a "Garden of Eden" situation where it tempts someone with either knowledge or power. Slowly gaining the trust of a young noble, using detect thoughts to grant them their hearts desire, and working their way into influencing the court.
Additionally, they could slither into various areas to assassinate someone, their Mind Fangs power can trigger off of the bite they deliver while polymorphed, making the first trike lethal to lesser npcs, and very painful to any PC of the appropriate levels.
And they could always serve as a leader of the local snake cult.
Another interesting tidbit: They can see through magical darkness. Though they have no way of casting darkness themselves (unless you swap something, and perhaps you should), they can be paired up with a pureblood illusionist or warlock to capitalize on it during combat. Though perhaps you should consider using Fly+ Eldritch blast. I am sure one of your PC's has used that combination at some time or another, and it would be delicious to have them on the receiving end for once.
Now for Malison's in general.
They are the priests and elite warriors of the Yaun-ti.
Warrior Malison's come in 5 different types, 3 from the MM and 2 more in Volo's chapter 2.
Type 1 (snake head) is the archer unit. By coating it's arrows in poison, it deals respectable damage with it's longbow. This is also the type of the Mind Whisperer.
Type 2 (snake arms) is the melee striker unit, it gets to bite twice (though I feel it really should have reach and various poison effects to make it interesting), dealing OK damage, but they don't have hands, so I doubt their general usefulness. I suppose it looks intimidating at least, however you could achieve similar melee prowess by giving one of the other types a Greatsword.
Type 3 (snake lower body) is another melee unit, but has a constrict attack that grapples targets while doing a smattering of damage. It also carries a longbow, just in case, but doesn't coat the arrows in poison (because it has a human head instead of a snake one). I would take them over the type 2's 90% of the time.
Types 4 and 5 share most of the same traits. They are also lower raking than the other Malison's perhaps due to the fact they are not venomous. But at least they have hands and can use weapons, so that's one thing they have over type 2's
Type 4 (snake tails) Should have a tail attack, perhaps with reach, and possibly some kind of knock prone mechanic. But they don't for some reason.
Type 5 (full body snake scales) should have extra natural armor, but again, don't for some reason.
Finally, Malison's have access to all of the Unusual Abilities that Abominations can get from chapter two, giving them a number of additional control options and body modifications to suit their role.