TL;DR More like “blech” Summoner. I have nothing nice to say here: the story is both badly written and offensive, although this episode only hints at the most troubling aspects.
Kelvin reincarnates from our world into a fantasy world, and learns his past self gave up his memories for OP skillz. Guided by the disembodied voice of a floating menu screen (actually the goddess Melfina, whom Kelvin apparently propositioned during his reincarnation sequence), Kelvin visits town and registers as an adventurer at the guild. Taking a bog-standard slime slaying quest, Kelvin defeats his first enemies and makes his first summoning contract with a slime he names Clotho. Later, Kelvin witnesses a slave trader hawking his “wares,” and seems especially interested in a beautiful elf girl on sale.
Uh, generic isekai power fantasy much? To complement the OP wish-fulfillment, this story builds up the worst kind of harem, where beautiful women inexplicably throw themselves into the bed of a strength-obsessed cad. The setting is bland, the humor falls flat, and you can’t swing a dead cat without hitting a cliche or six. Now, with spoilers from the light novel, let’s talk about how problematic the protagonist is: Kelvin is a reckless battle junkie who constantly provokes needless fights or handicaps himself against dangerous opponents (thereby putting others at risk) just to get his jollies. He also has no scruples over becoming the type of slaveholder who sleeps with his slaves (which, due to the power disparity, is definitively rape as far as I’m concerned). I’m actually wondering if the show will age up the elf girl, because on top of being a slave, she’s actually underage when Kelvin starts sleeping with her in the novels (he really is that revolting). The Naofumi x Raphtalia relationship in Shield Hero is unimpeachably wholesome compared to how Kelvin behaves. I wrote this first impression so you won’t waste twenty-odd minutes watching this show. You’re welcome.
Black Summoner is streaming on Crunchyroll, though I can’t imagine why you’d want to watch it.