Ask for whatever you want
Eswet
You are such a strange fellow:
Clever, yet a fool...
I have come for your sorrow —
My kit of souls is full.
"And again about the devil"
Luellin.
The troubles started together with Lina's 'time of the month'. Although, to be more precise, they started even earlier, when Zelgadiss, having found another ruin, absolutely refused to have company as he left. Before that Amelia was called home by her Daddy, so Lina and Gourry attempted to convince Zel to let them come along, but failed, gave up and headed to Atlas, to meet there precisely in a week.
Two days after they parted ways with Zel, our travelers came across a gang of beast-people. Lina had just lost her magic ability, so she was politely standing behind Gourry's back, finishing off those bandits still alive. As usually in such cases, Gourry got away with just a few scratches. The only problem was that the bandits' weapons were poisoned. That was completely against the rules!
So now Gourry was quietly kicking the bucket under a bush, and Lina, cursing wildly, on the edge of tears, was trying to cast at least a tiniest Recovery. But Recovery never came. The greenish-looking Gourry was smiling wanely and telling her not to worry. Lina displayed good timing remembering that it wasn't the best idea to hit him on the head. The minutes passed, Gourry was becoming more and more greenish, and Lina didn't know what to do with herself and quietly cursed Zelgadiss who decided to desert them at such a well-chosen moment!
"Trouble, Miss Lina?" a soft voice inquired behind her ear.
"Ah, that's you, Xellos," she muttered dully, but then her head was visited by a, frankly speaking, nasty thought. Would there be any of her friends around, the thought could never have a right to exist, but at that time...
"Xellos! I beg you to help me," the words came with surprising ease.
"Eh?.. But I..."
"Shut up! I know you won't help just like that. Look, save Gourry and ask me for whatever you want!"
The mazoku's eyes popped out of his head.
"Miss Lina, have I heard you right?"
"Yes, you have. Whatever you want."
Lina hoped Xellos didn't notice her shaking knees. She has just practically exchanged her soul and body for Gourry's life. To ask a mazoku for something in such a way meant to sell the rest of your life cheap and stupid. Even the Pact had more benefits. But Lina didn't see any other solution.
Xellos started opening his mouth, but then closed it, nodded and disappeared. Several seconds later he reappeared holding Sylphiel under his arm. Her messy clothes hinted that she was pulled right out of bed.
"Oh, Gourry-dear!.." Sylphiel cried, then ran up to the almost lifeless warrior and cast a Recovery whole-heartedly: with white lightnings, heavenly light and other special effects. Gourry flapped his eyelashes once, frightened, and was instantly off sleeping. His face gradually returned to the normal color. (Later, he couldn't remember a thing about his healing, and Lina, when asked, only waved dismissively). Sylphiel relaxed, yawned and was immediately carried away by Xellos to wherever he brought her from.
"She will think she dreamt this all," the mazoku said, returning. "Miss Lina, I'm surprised..."
"Xellos, quit prying. Better name your price."
"Yare-yare... Miss Lina, I haven't come up with anything to ask of you yet. Let's put this discussion off for... some other time, all right?" Before the answer ever came, Xellos vanished. Lina gnashed her teeth.
During the next month her friends couldn't help wondering about the red-haired sorceress's behavior. She plunged into most dangerous adventures, ate exclusively the most exotic (and enormously expensive!) dishes, wasted so much money that Gourry even once asked her if she was a counterfeiter (and received his share at once, of course!). Zelgadiss turned out to have a little more insight and inquired whether Lina decided to kill herself or get married. It was useless to beat the Chimera, so Lina confined herself to a fireball, and Zel thought it best to keep quiet.
Xellos appeared one late evening when the Slayers were already preparing to sleep. After hearing the stock greetings (a moderately suspicious one from Zel, a sincerely cheerful one from Gourry and a gritted-teeth one from Lina), he made some small talk for several minutes, and then said innocently, "Miss Lina, may I ask you to walk with me under the Moon? We have something to discuss..."
Lina waited a moment as her heart skipped a beat, then silently rose to her feet. Zelgadiss and Gourry watched them walk away, then exchanged unsure glances. ("Could it really be about marriage?.." Zel thought. "There's something I don't get again..." Gourry thought.) So they went to sleep, deciding it was safer not to interfere with Lina and Xellos's relationship.
Meanwhile Xellos kept twaddling. And he was so entertaining and carefree that Lina soon gave up her worries and decided to spend her last night with pleasure. That's why they walked through the forest and sat on a cliff's edge, feet dangling over a river, told stories of their adventures, bathed, contemplated the Moon and night flowers and even kissed once ("To hellmaster's grandmother with all that! I have a right to know how it feels!" Lina thought. "Well, not bad at all!" she thought after, hmm, fifteen minutes. What Xellos thought about that remained a secret.)
Eventually, when half of the sky was saturated by the dawn's blush and Lina's eyes no longer held open, Xellos said, smiling broadely,
"Well, we had enough, hadn't we? Lina, you'll even get some sleep today, let me walk you to the fire."
"And what about our, er, deal?" Lina opened one eye in surprise (almost like Xellos, really!). "I thought, you'd tell me..."
"Ah, that! You know, I thought about it and decided that I'd reckon this time out towards payment of the debt. Do you mind?"
Lina didn't get it at first. But when she did...
In short, Zelgadiss and Gourry were woken by Lina's screams and sounds of explosions, and for a pretty long time they could contemplate the morning sky coloured with green and red and decorated with flitting silhouettes of Xellos dodging the raging sorceress's spells and laughing his head off.