Spear would not be my first choice for the terminology no...they function as spears but they are not true spears (as in purposely designed for combat or hunting). The spears used by Cavemen were more then just sharpened sticks, they developed into a fastened piece of sharp flint or stone attached to a wooden shaft with sinew, vines, etc., would indeed make it a primitive spear (that's the best technology could offer at the time), a sharp pointy piece of wood is just that. But because of the nature of spears, if you read on I'm more willing to let the term slide, specifically because the wrought iron fence post Jason wields has a definite spear shape. The axe name on the other hand is horrible, Jason's a murderer he doesn't really "battle" anyone, and it's an axe used for cutting down trees..but I've given up on that as too many here have bitched about it...and am merely replying to your post.
That's somewhat wrong about shuriken, breaking up the name "shuriken" it means hidden hand blade in english, samurai and ashigaru adopted them originally but during the infancy of ninjutsu arts the shinobi used whatever they had on hand because originally they were from the poor farmer class and would simply modify their farming implements, shurikenjutsu wasn't even initially one of the ninja arts, but as they moved to the mountains, their arts developed so to did their craft classification, smithing, techniques, reputations as spies and assassins and defining characteristics, they would learn and steal new types from fallen samurai and ashigaru and made them better, there are bo-shuriken which are typically sharpened metal spikes of varying shapes and sizes, and there are hira shuriken (aka shaken) which are the popular throwing star variety, when low on materials they could make crude versions of these two types, even using large modified coins or other pieces of metal, although the techniques would mean they would have to at least be near their purposed designs. They were often used as either a distraction device, or to target soft parts of a body in an effort to allow minor injury or nuisance to a target. However the most clever shinobi could dip them in poison they'd made and make them lethal either in throwing and injuring with them, or leaving them lying around to be picked up with a contact poison. Others account of them being left in feces or animal matter to facilitate tetanus bacteria, back then there was little treatment for the effect of the infection. They could also be employed as a close range weapon in times of last resort. A friend of mine is a modern day practitioner of ninpo at the Banri Dojo and practices shurikenjutsu among many other arts involved with ninjutsu. Anyways that's it for now!!