Try talking to the skeleton

You decide that it won't hurt if you at least try talking to the undead warrior. "Um... hi." You say as you look at the skeleton.

"Hello and welcome." The skeleton responds. Well, at least he's not in a hurry to attack you.

"So... you're my opponent?"

"Yes. You must defeat me to proceed. There's no other way - the key to open the doors won't appear until I am defeated. If you can't beat me you don't stand a chance against the real opponents you will encounter here." The skelton answers matter-of-factly.

"So this is just a simple test..." You say to yourself as you process the information. "Anything else you can tell me?"

"Sorry, that's all I know. The others can tell you more... if you can find them."

You try a few more questions before giving up. Looks like you have learned everything you can from this conversation. Time to decide what to do...