Artist masara_(acgarts) and sixi1990

I need help determining whether they're the same artist or is this a plagiarism case.

masara_(acgarts)
http://www.pixiv.net/member.php?id=1918600
http://blog.acgarts.com (circle blog, has multiple artists)

sixi1990
http://www.pixiv.net/member.php?id=2569740
http://hi.baidu.com/%D0%A1%BA%EF%B8%E71990/home (inaccessible)

Both are Chinese, same age and gender, nickname are Masara in a way (マサラちやん vs Masara_阿飘) but different blood type (A vs B). Notably, the former pixiv account has picture titles, artist's commentary and tags in Japanese, while the latter are all in Chinese. The former also has self introduction in the profile in Japanese, the latter doesn't say anything. All these details might indicate sixi1990/Masara_阿飘 doesn't know Japanese.

But I'm not entirely sure this is plagiarism because all of the latter's arts appeared to be a little bit fuller (albeit smaller resolution) compared to the former's:

post #892707 vs illust #25813733&page=2
post #896434 vs post #1383516
etc.

The former account (1918600) claims to be a joint account of this Chinese doujin circle:

Chinese name: 宇宙起源研究社 (Yuzhou Qiyuan Yanjiu she, Research Society of the Cosmic Origins)
Japanese name: A.C.G.アーツ (ACGARTS)
Leader: 曲发兄贵 (Qu fa Aniki) (His Sina weibo miniblog account is here)
Official HP: http://www.acgarts.com/

Its self introduction page says:

This is our dedicated pixiv account for joint announcements by circle members who can't speak Japanese.

Thanks henmere, then I'll ask for aliasing to masara_(acgarts): forum #86502. Wrote the wiki for it too.

Note that masara_(acgarts) may upload the other members' works.