You are correct that pacts, blood-based or non, vary considerably. What might be included in such a relationship, and who, are part of those variables. Where Satanism and the LHP are concerned it does make sense that we're talking about the magician or occultist in question making the thing, and what might be described as 'dark forces' are a reasonable candidate for the alliance. Your specificity about what is offered is too restricted. Some offer more than mere 'alliance', such as service, or a (sacrificial) offering, some aspect of what they own, control, or are. Since Satanism is only less than half a century old you should not expect many conventions or orthodoxies to have grown up around it, especially given the predilection for atheism and materialism compounding the Satanic trajectory. Those appealing to 'Father Satan' or 'The Master' may have something to add to the description of 'having the dark forces looking out for their concerns', and demonolaters probably have a section with similar views.
Pacts per se do not necessarily include any kind of agreement document, or 'contract'. That is a facet heavily popularized by Faustian tradition, in which Christians attempted to gain from The Underworld Jailer Devil on a trade for their eternal soul. Granted the ostensible terms whereby this soul would be lost, usually some great sum, attainment of fame, or knowledge, was sought in these stories. In most, the 'moral' is that the sum or attainment count as nothing against eternal life (an endless afterlife experience that the God of the Universe could provide) which is available through their local ecclesiastic dispensor of forgiveness and 'Salvation'. Goethe turned the Faustian legend into a Christian Salvation story itself.
There are so many different stories that I suppose I am not surprised, though cannot specifically recall, a mention of 'acknowledging Satan as the true ruler of this earth'. Typical Christians don't always put things in these terms, but satanic Christians or Satanists might do so, and especially as part of some kind of Faustian contract. You should know that primarily those who engage these kinds of pacts are imbalanced, unstable, religiously-deluded, ignorant, and never receive or attain to the contracted terms. Religious confuse story and history, reality and fantasy, and so exaggerate the importance of rites, spells, and magical activities such as pact-making.
The 'official' aspect of Satanism has come into being almost immediately with the attempt to regulate and administrate it through cults, with dominating priesthoods duplicating Christian models of hierarchy and power-delegation. The attempt to describe 'real Satanists' began long before religious Satanism was conceived, in the fantasies of Christian subversion ideologists. They concocted heinous travesties of their religion in their mind and described all manner of immoral prerequisite to titillate in consideration of the 'evils' of their enemies. When religious Satanism was created in the latter part of the 20th century there was little more than a fee and a questionaire (if that) to gate the membership in the churches, temples, 'sinagogues', and cathedrals, many of which came to exist via the thin tendrils of computer networks. To 'officially' become a Satanist simply requires that you engage an ordeal that marks the transition to that modality or to actually achieve some minimum set of ideals which you designate. The fulcrum of leverage in Satanism is the individual.
Satanists, those who engage pacts or otherwise, are not provided superordinary or supernatural protection by our demon guardians or gods, by my understanding. We may receive internal bolstering and magical protection, for what it is worth, and may be shown new and important ways to view the world and our situations. 'The dark forces' is a metaphorical referent. It relates to uncommon, wrathful, demonic, questionable agents, intelligences, and entities as perceived by the pact-maker. All such relationships (as are those amongst humans) are negotiated in some way or another, even if within very limited constraints.
The method by which we engage such relationships would ordinarily be the kind of 'rite of passage' you are speaking about, but in combination with the Christian contextual culture and our proper engagement of the Mode of Martyrdom, rather than the Way of Whining, it may become a transformative ordeal for us even by virtue of having forged this adventurous and daring bond. The typical religious hasn't the head or heart for this steep an attitude, however, and the ordeals are usually restricted to social dramas of combat interior to the Satanic milieu, their immediate family, or to successive initiations wherein they may become puffed up and arrogant about it all. That 'old life to new life' thing should only happen once where Satanism is concerned, or it wasn't a very effective transition. People engage what is called Black Masses for this purpose (something you create as a travesty of your own former religion - see the Satanic Bible for a decent description of its purpose and ostensible form).
@Venus: Thank you very much for making that video and participating in threads such as these. I have offered a supplemental fatwa which is available via my SIN personal page on 'How to Sell Your Soul to Satan' - something which you recommend against, and while I can understand why you do so, I think it could be helpful to some satanic Christians and Satanists of the proper character and intelligence. :)
Grand Mufti of Satanism