HR diagram of HeZAMS with and without the EIS and evolutionary tracks of He stars with 6 and 30 M_⊙. The green and blue lines represent the WN and WC sequences, respectively. The gray lines represent the evolutionary track of the He stars without the EIS, obtained using MLT++. The red dotted line represents the HeZAMS without the EIS, while the red solid line represents the HeZAMS with the EIS. The orange line corresponds to the ZAMS of normal stars.