BSSM Eternity introduces but one new senshi to the universe of Sailormoon. Still, reading her profile early will spoil some parts of the series. I suggest you don't read the profiles until after she's been introduced, but it is up to you.
New Senshi of the Legacy</head>
Bishojo Senshi Sailormoon Eternity
Sailoreternity, Hatashinai Yume