The Love Pentagram Theory
The individuals chosen were the normal Slayers group plus Sylphiel due to her having a definite affection for Gourry. The pentagram because it is used extensively in Slayers, also, specifically at the end of the Slayers OAV's there are octagrams, this would allow one to include other characters but it would require even greater speculation on the part of the person. As far as this one goes most of it is quite acceptable, Gourry is connected to Sylphiel and Lina, the box on the line between Gourry and Lina represents mutual affection to some degree. As you can see Sylphiel only has arrows pointing from her to Gourry indicating that it is a one way thing, if Gourry did like her back she would definitely act on it. From Lina there is a line going to Zelgadiss, here is one point that is up for speculation, while I would not call their relationship love there is a bond between the two that might prove to go deeper if probed, again, this is speculation. From Zelgadiss there is another line that leads to Amelia, this one is boxed showing the mutual affection that probably exists, exp. confirmed to some extent by the ending of Slayers Try and that they are traveling together to arrive during the Slayers Premium movie also there are in show references. The only line that does not fit is the Amelia - Sylphiel line, that is up for quite some debate. But you never know, this could be some sort of hidden message? Additionally the corners show even more alternate pairings but nothing like the lines show, the pentagram itself is just a good way to come up with couplings in fanfiction.
This pentagram has the orders adjusted to provide what I call the Flow Model Pentagram. The best place to start is with Sylphiel, she likes Gourry, one sided relationship, line to Gourry indicates 'direction of love' from there Gourry has affection for Lina, line of love goes toward Lina, From here things are odd, it goes to Amelia? Anyways, who knows, From Amelia it goes to Zelgadiss which of course makes heavy sense, and finally it goes from Zelgadiss to Sylphiel, I could see that working, he is quite nice to her at times. In this model no one is really happy in the end but it is interesting that it flows like that.
In conclusion, none of this probably means anything, yes, I could imagine the creators of Slayers getting together and formulating some scheme involving the pentagram relationship sceme simply because it would have ties to the show, but what about the octagram? I can imagine a lot of things but just because I can imagine it does not make it so. Regardless, this is just meant to give people something interesting to think about. Plus, the 'graphs' are interesting as well.