A bit of foreshadowing?

[ManaMinori 4,149]

During the season finale, the Mane 6 and Spike were trapped in Tartarus. Why was Spike trapped as well? Was the "I'm here too!" thing from him truly just a gag? I don't think so. The fact that he so adamantly insists that there's a 7th member there actually draws attention back to the sheield of friendship that's in the new season opener. There are 6 gems around Twilight's Sparkle's symbol, which is front and center. One of those gems is Green....I think the writers may be on to something and alluding to something in season 9 concerning Spike....

a 7th element, perhaps?

 

[Thrond 3,271]

Could be. Spike has his own mini-throne in the Castle, after all, and he’s as close a friend to Twilight as anyone else. Doesn’t seem the Elements of Harmony are relevant anymore, though.