まるです。

「ふんふん、これは何ですか？」
Maru:[Sniff…What is this?]

それは鬼のお面ですよ。今日は節分なので。
It is the mask of ogre. Because it is Setsubun today.
*Setsubun: Wiki
ということで、鬼役をお願いしますね。
So Maru, I ask you for the role of ogre.

「どうして鬼役ですか！！」
Maru:[Why? Why am I the role of ogre?]

まあまあ、まるさんには後でカリカリをあげますから。年の数だけ。
Oh, without saying so.
I am going to give you later as many dry foods as your age.

「４つぶ！」
Maru:[Only four!]
*It is a custom to eat as many roasted soybeans as your age.