Ok, here we go:
For Naruto: As it turn out, he actually learned two jutsus from the forbidden scroll, the second wich needed the user to know Kage Bunshin, he just never tought that the last one would be actually usefull in anything.
It allow the user to project his/her mind (a la Yamanaka) to any solid bunshin made by him/her that is inside the jutsu range (wich can go up to a few KILOMETERS with good anough control) and then go to other ones instantly, bringing the memories of the user and the other bunshins he/she went trough (like with the memory trick, but without dispelling).
The cons are that it leaves the userÆs original body vulnerable, but even a bunshin can use that jutsu as long as he/she have anough shakra. The pros are that it gives the user perfect instinctual awareness of where all Bunshins are while changing from one to another and the insane cordenation it gives to all of them.
The source is the game Battlefield Modern Warfare, in wich the GamePlay allows the player to switch between different soldiers enytime anywhere, as long as there are any left.
For Sakura: As it turn out, her ancestors werenÆt natives of Konoha, they went there after a failed coup dÆetat (that was stoped before it even began) against the government of their home country. When they came to Konoha, not all of them wanted to keep on living as ninjas. ôWhat that has to do with anything?ö you ask. Well, it so happened that one of the familyÆs heiloom was passed down to Sakura when her parents came to know what went down in Wave Country.
It was a sealing scroll that contained artefacts from the times of war before the villages came to be. You know, the time when phisical gods walked around PWNING N00Bs. Said artefacts were three very dengarous, semi-independent, almost santient puppets, crafted with jutsus and technology long lost. They only need a steady supply of chakra and maintenance and then you could let they could go on their way to acomplish their given missions.
One is a small-man sized one especialized in silent assasinations, able to move around COMPLETELY unnoticed if needed and can ruin anyoneÆs day fighing at close quartes. The second one could easily pass as young woman unless your are a very good sensor or can see peoples innard with just a glance, especialised in infiltration but can also hold its own ground in battles. The last one, a huge humanoid that weight half a ton, is the only one made with only combat in mind, it is a juggernaut that could go against gigantic summoned creatures and win.
It would take Sakura a long time and a lot of practice to be able to sustain all three at the same time, not counting learning how to fix them, and dealing with their cut-throat aproach to any kind of trouble.
Source is the game Ninja Warrios Again.
To Shikamaru: Between the NaraÆs shadow controlling jutsus there are a few that involve the direct use the power that can be drawn from shadows. A secret known only by the oldest members of the clan and itÆs leader is the fact that before joining Konoha, the Naras were a bunch of bloodthirsty assassins before being put in their place by the Senjuu. Back then, their jutsus were fueled by the mythical Black Chakra, sometimes at the cost of their sanity.
Fundamentally different from normal chakra, the Black Chakra is linked with nature like Sage Chakra and almost as strong. It allow the user to use the other NaraÆs jutsus without hand-seals and more efficiently, also giving then a myriad of abilities. Including but not limited to: easy long range teleportation, creation and control of demon-like creatures that apparently feed on peopleÆs souls and the power to fuse with oneÆs shadow gaining great strength and speed while entering a berserker-like state.
This power, however, donÆt come without its drawbacks. Using the Black Shakra give a great feeling of strength that can become addictive if the user isnÆt careful.
Source is the game/franchise Kingdom hearts, from the not-really-explained-in-depth power of darkness and SoraÆs Anti-Form.
