This strange, frog-like creature is Guli, a Pond Spirit. Much like his spiritual cousin, Qui, Guli is the physical manifestation of a place called Guli Pond, a magical pond that the spirit controls and is necessary to the balance of life. Guli can sense when someone comes close to the pond or when something happens to it, but this is generally unnecessary. Guli Pond is hidden in the very middle of a large, mountainous ring, which would take most people a great amount of hardship and time to actually scale-- although it takes Guli himself one, great leap to bound over the mountainous ring and to face the outside world.
Guli's personality can be described as "naive". Over his very long life, the spirit has not taken it upon himself to learn the ways of mortals, or to mingle and read and become educated. Instead, Guli speaks of himself in the third person- "Guli likes this, Guli is sorry, is it okay if Guli eats this?"-- and is often left curious about all sorts of things and people outside of his pond. He treats most mortals with an amount of fascination and awe.. and a great deal of lust, as a side-effect of being a spirit with a physical manifestation; sex, and sexual things, are one of Guli's favorite ways to pass the time. Guli in particular, because of how little he visits the land of mortals, has a great deal of pent-up needs, and expresses them by openly flirting with, touching, and expressing interest in fucking mortals (or immortals, if he meets any of them, actually. Pretty much anybody with a physical body.) He's not nearly as tricky and predatory about it as his spiritual cousin, but he can be pretty aggressively needy if need-be. On the plus-side, his body is especially sensitive to acts of a sexual nature, so not only will fucking somebody with his cock or being fucked in his especially plush rear work, but even sexual use of his tongue/mouth can satiate the spirit.
When it comes to vore, the pond spirit is also as openly naive and almost insatiable. Although not nearly as much as his sexual appetite, Guli's physical body inflicts on him a need to eat, even though he is immortal. His two primary methods for this are the simple way- by actually swallowing somebody down his incredibly stretchy throat- or by sucking out their soul and leaving them a mindless husk of their former self. If need-be, Guli can choose to only suck out a portion of his prey's soul, although they'd have to be pretty damn friendly and ask nicely for Guli to spare them. Souls are, after all, a very physical and very delicious thing to the pond spirit. Insomuch as being prey, Guli is a bit of a tangy meal, but because of his slick body, he's quite easy to swallow. His soul can be sucked from his body, but it is merely a small piece of his link in the chain of the universe, and is easily replenished/stocked by swallowing the souls of others. No matter what, Guli will eventually reform back at Guli Pond, unable to die.
So what can Guli actually do, as far as abilities go, as the spirit of the pond? His body, besides being able to regenerate after death and suck out the souls of prey, is also incredibly stretchy. This isn't just useful for swallowing and holding larger meals, but also allows the spirit to stretch his limbs and muscles, and greatly increase (or decrease) his own height. His skin is incredibly pliable because of how stretchy he is, making it almost impossible to cut or impale his body. His tongue, equally stretchy, has the inhuman strength necessary to bind most prey, and is prehensile, every inch of it able to be controlled easily by Guli himself. His legs are the strongest part of his body, by far, allowing him to leap- almost fly- great distances at great speeds, and thrust away anyone but the strongest of unwanted predators. Guli's skin even secretes a thin membrane of slick, sticky fluid, keeping his body sleek. The fluid that it secretes has a very potent aphrodisiac laced into it that, when ingested, causes other creatures to become noticeably aroused, and amorous against their wills. This is useful for convincing even particularly prude mortal, or for distracting them when Guli becomes particularly hungry. It's even stopped a few predators who tasted Guli and then changed their minds because they wanted to fuck the spirit. Unsurprisingly, Guli can also manipulate, and control, water, summoning torrents of it if necessary, or using water that already exists around him.