To get the free base character sprites download for RPG Maker MV do the following:
1. Go to the Japanese MV website which is at this link:
http://tkool.jp/mv/
You'll should see what is in Picture 1 when you get to it.
2.) Scroll down till you come to the part as indicated in Picture 2 in the page and click on the blue link box button, I also indicted in the Picture 2.
3. You'll have a Japanese EULA pop up as shown in Picture 3.
You click the blue link box as indicted in Picture 3 at the end to download the zip file of the sprites.
A rough slightly paraphrased for clarity translation of the EULA is as follows:
Terms of Service
Use in other software including other Maker series is prohibited.
You may with out having a registered copy of RPG Maker MV to distribute the material and modify the material and distribute the modified version for free.
However, if you want to release a game using that used this material in anyway you must own a registered copy of RPG Maker MV.
The selling of this material and of modified versions or the processing of it for material sales and the material for secondary distribution is prohibited.
Translation Notes: If your not clear about the 3rd term and the 2nd term is basically saying you can't sell the material, or separate resources made with it. (New sprites made from them for example.) This would also include a spiriting program and additions to programs to make RPG Maker MV sprites using them given my understanding of the EULA.
You can still sell your game if you use them or a modified version of them in it as long as you own a registered copy of RPG Maker MV.