The choice is obvious! You are a Demon Lord, after all, so a Warlock Specialization is a pretty much a no-brainer! Spells of massive destruction, various demons at your command, what's not to like? Not to mention your probably-sister so kindly asked you to summon minions, so why make a bad first impression? And perhaps asking her name and getting to know her would help a lot in that regard.

Figuring that basic common courtesy would be to at least ask for her name, you do just that. “Before that, could you at least tell me your name?”

“A-ah, yes of course, how rude of me!” The girl gets flustered. “My name is Ariadne!”

With basic courtesy out of the way, you return to your Status bar to choose your second Specialization. Obviously it’s going to be Sexomancer because you’re a pervert and there’s a good chance that you have plans to lewd it with your own summonings and/or underlings. Perhaps even have them lewd each other? Why stop there? What's the point of conquering the world if you can't conquer it sexually? After all, taking over the world is a lot of work, so you have to find the right motivation to bother with it in the first place!

You take a quick look at your warlock spells. The list is not as impressive as you perhaps hoped.

[Shadow Bolt - lvl 1

Deals magic damage to a single target.]

[Summon Imps - lvl 1

Summons 3 Imps under your direct command.]

[Drain Life – lvl 1

Deals magic damage to a single target, healing you for the same amount.]

Then again you are only starting out. Sure, "three imps" does not sound a lot, but you have enough mana to use the skill quite a few times, so if anything it will actually help you level the skill faster. However, you will need to establish a baseline for how strong your spells and minions are. And the sooner the better.

Taking a gander at the Sexomancer spells you see the following:

[Dick Enlargement - lvl 1

Increases the dick of a single target. Target has to have a dick.]

[Aphrodisiac Mist - lvl 1

Unleashes an aphrodisiac mist in a small area, causing all who breathe in the mist to become aroused.]

[Submission - lvl 1

Attacks the mind of a single target, making it more willing to follow your commands.]

“My Lord? Is everything alright?” Ariadne tilts her head slightly.

Might as well try out one of the spells and see how it goes.