I believe that is the soul rune - a rune which you can't make, neither at a runecrafting altar nor with the new wicked hood. The only way to make it is at the Ourania altar, also known as the ZMI altar, which makes random runes, including the soul rune. It can also be bought from stores - and of course traded via the Grand Exchange.
Get about 5 rune scimitars from the highest bestiary in the Stronghold of Player Safety.
full rune is a good option. lots of people go for elite black now days but im not sure how much it is
The maker of Runescape by the name of Andrew. Rune is a made-up material that is ONLY used in runescape
Rune Pickaxe - 18,145gp - 20,055gp
if u mean by highest as in money i think its guilded armor but that's off the top of my head. If you mean by best then rune armor
For F2p it would be the Rune 2Hander as it has the highest str bonus, but i prefer the scimitar:D
If it is a shield with good defense against ranged attacks your best bet is: Members: Granite Shield Non Members: Rune Kiteshield
Rune berserker no question. Rune Spike is worst, 2nd is rune kite, and best is rune berskerker.
You use rune essence/pure essence on a altar. (runecrafting)
Mithril, possibly Rune (rune is a sort of greeny-blue)
Rune Med-Helmet.
summoning