Rescued hostages will sometimes say 'I knew you would come. Thank you.' in a very sincere voice, which makes a nice change from shrieking clones and burbling corporate cyborgs. Especially heartwarming as the Alert missions sometimes label the Rescue missions as "Abducted Civilian" or "Detained Diplomat Located". Maybe the Tenno aren't as monstrous as they seem.
Evacuating a mission invaded by the Grustrag Three results in the Lotus saying 'The mission was aborted, but you are safe, and that means we won today.' Well, unless she's just worried about losing a valuable resource. Hard to tell really, it's that sort of game.
If the players manage to defeat them, she scolds them for disobeying her—and putting themselves in danger. At the end of the mission, she says she is just happy they're all safe.
The concern in her voice as she tells the players to run away is equal parts Heartwarming and utter Nightmare Fuel because what could possibly scare the Lotus?
If you get captured by the G3, but your team stays to help you instead of getting out of there (when the one that captured you gets killed, you are freed from the cage). Many thankful messages ensue.
This all makes sense with the updated prologue missions - Vor even outright says he's trying to 'steal [the Tenno] from their mother's [Lotus] embrace'. Perhaps she caresdeeply for them.
Putting yourself in danger to save a downed teammate can easily be this in the right situation.
Or the flip side of this, seeing someone running to save you.
To elaborate, in public matches, with people from all walks of life being able to play, people tend to Kill Steal alot,and run through objectives as quick as possible. In effect, these people have probably no reason to help you as it will just slow them down. But that doesn't matter apparently, as going in full force to them is clearly more important then just breezing through the mission.
Since Update 14 was released, the Tenno have been able to create domesticated Kubrows (dog-like creatures), take care of them as they grow up, and show them affection to keep their spirits up before bringing them on missions, including petting and scratching them. It really shows there's more to the Tenno than just being deadly space ninjas that kill everything in their path without a second thought; they actually have a soft side.
A meta example- in the wee hours of the morning of June 18, 2014, the devs posted a video of what to expect in the update coming out later that day- an update that had been delayed many weeks by that point, much to many player's annoyance. The general reaction to said video? Concern that the devs looked extremely overworked in the video, and a petition that they all should get some sleep and save working on the update for next week.
In the updated prologue, Lotus pulling all stops to make sure you get off Earth alive. "I can't lose another one" indeed.
Update 15 brings us Syndicates, smaller organizations separate from Grineer or Corpus with their own goals and agenda. Some Syndicates' aims may be quite heart-warming, for example:
Steel Meridian, led by a Grineer defector, wants to protect small human colonies that are unable to stand for themselves.
It's pretty inspiring to see a Grineer, of all people, totally casting off the whole genetic-superiority thing in favor of a firm and unrelenting creed to protect the innocent (especially since, being a clone, the Steel Meridian leader could be suffering from the hereditary psychosis and degeneration). Reaching a high enough rank actually leads to her commenting "I was wrong about you. You're a hero to these people. And to me."
The Perrin Sequence, a group of Corpus merchants who, instead of profiting off the conflict, use their trade to restore order and bring prosperity to the system.
New Loka, whose goal is to restore planet Earth and the human race from their current degraded state.
However, there's another side to the new loka's objectives, sure they want to restore the human race to it's original form, but they seem to want to do it by eliminating any and all "impure" individuals, among the things their leader/representative says when you're against them are: "You are just like the rest. Tainted and ruined beyond salvation.", and (when sending their death squad after you) "The impure, the unworthy have no future." and "You will be cleansed."
Minor NPC activities in Relay can make you feel a bit fuzzy when you look at them.
In Steel Meridian syndicate room, there is a former Grineer soldier who is working dutifully... while glancing at a potted plant. Eventually he goes straight to the greenery and pets a leaf with a small smile. It's heartwarming to know that the Grineer can care deeply for anything, really.
There's a man (supposedly) teaching a MOA inside Perrin Sequence syndicate room, with the robot acting like a cute puppy.