But it was such a cool 5 minute fight! And like, there was blood and stuff!
The badly written character interactions of the main cast and the truly ancient Generic Shonen cliché of the "fateful" (read: random with zero build up) encounter with powerspike bad guy from the series billed as the "Grandfather of Isekai" doesn't matter.
edit:
This episode was a significant step backward for a series that has otherwise actually lived up to its legend of quality.
And since it still isn't the actual first modern isekai (just in the shonen/seinen genres), I hold it to a significantly higher standard due to the reputation that its LN fans give it.